Lanoxin
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Questions & Answers
Side Effects & Adverse Reactions
Because digoxin slows sinoatrial and AV conduction, the drug commonly prolongs the PR interval. The drug may cause severe sinus bradycardia or sinoatrial block in patients with pre-existing sinus node disease and may cause advanced or complete heart block in patients with pre-existing incomplete AV block. In such patients consideration should be given to the insertion of a pacemaker before treatment with digoxin.
After intravenous digoxin therapy, some patients with paroxysmal atrial fibrillation or flutter and a coexisting accessory AV pathway have developed increased antegrade conduction across the accessory pathway bypassing the AV node, leading to a very rapid ventricular response or ventricular fibrillation. Unless conduction down the accessory pathway has been blocked (either pharmacologically or by surgery), digoxin should not be used in such patients. The treatment of paroxysmal supraventricular tachycardia in such patients is usually direct-current cardioversion.
Patients with certain disorders involving heart failure associated with preserved left ventricular ejection fraction may be particularly susceptible to toxicity of the drug. Such disorders include restrictive cardiomyopathy, constrictive pericarditis, amyloid heart disease, and acute cor pulmonale. Patients with idiopathic hypertrophic subaortic stenosis may have worsening of the outflow obstruction due to the inotropic effects of digoxin. Digoxin should generally be avoided in these patients, although it has been used for ventricular rate control in the subgroup of patients with atrial fibrillation.
Legal Issues
There is currently no legal information available for this drug.
FDA Safety Alerts
There are currently no FDA safety alerts available for this drug.
Manufacturer Warnings
There is currently no manufacturer warning information available for this drug.
FDA Labeling Changes
There are currently no FDA labeling changes available for this drug.
Uses
LANOXIN is indicated for the treatment of mild to moderate heart failure. LANOXIN increases left ventricular ejection fraction and improves heart failure symptoms as evidenced by exercise capacity and heart failure-related hospitalizations and emergency care, while having no effect on mortality. Where possible, LANOXIN should be used with a diuretic and an angiotensin-converting enzyme inhibitor, but an optimal order for starting these 3 drugs cannot be specified.
LANOXIN is indicated for the control of ventricular response rate in patients with chronic atrial fibrillation.
History
There is currently no drug history available for this drug.
Other Information
LANOXIN (digoxin) is one of the cardiac (or digitalis) glycosides, a closely related group of drugs having in common specific effects on the myocardium. These drugs are found in a number of plants. Digoxin is extracted from the leaves of Digitalis lanata . The term “digitalis” is used to designate the whole group of glycosides. The glycosides are composed of 2 portions: a sugar and a cardenolide (hence “glycosides”).
Digoxin is described chemically as (3β,5β,12β)-3-[(O-2,6-dideoxy-β-D-ribo-hexopyranosyl-(1→4)-O-2,6-dideoxy-β-D-ribo-hexopyranosyl-(1→4)-2,6-dideoxy-β-D-ribo-hexopyranosyl)oxy]-12,14-dihydroxy-card-20(22)-enolide. Its molecular formula is C41H64O14, its molecular weight is 780.95, and its structural formula is:
Digoxin exists as odorless white crystals that melt with decomposition above 230°C. The drug is practically insoluble in water and in ether; slightly soluble in diluted (50%) alcohol and in chloroform; and freely soluble in pyridine.
LANOXIN Injection is a sterile solution of digoxin for intravenous or intramuscular injection. The vehicle contains 40% propylene glycol and 10% alcohol. The injection is buffered to a pH of 6.8 to 7.2 with 0.17% dibasic sodium phosphate and 0.08% anhydrous citric acid. Each 2-mL ampul contains 500 mcg (0.5 mg) digoxin (250 mcg [0.25 mg] per mL). Dilution is not required.
Sources
Lanoxin Manufacturers
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Cardinal Health
![Lanoxin (Digoxin) Injection, Solution [Cardinal Health]](/wp-content/themes/bootstrap/assets/img/loading2.gif)
Lanoxin | Cardinal Health
GeneralRecommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications.
Parenteral administration of digoxin should be used only when the need for rapid digitalization is urgent or when the drug cannot be taken orally. Intramuscular injection can lead to severe pain at the injection site, thus intravenous administration is preferred. If the drug must be administered by the intramuscular route, it should be injected deep into the muscle followed by massage. No more than 500 mcg (2 mL) should be injected into a single site.
LANOXIN Injection can be administered undiluted or diluted with a 4-fold or greater volume of Sterile Water for Injection, 0.9% Sodium Chloride Injection, or 5% Dextrose Injection. The use of less than a 4-fold volume of diluent could lead to precipitation of the digoxin. Immediate use of the diluted product is recommended.
If tuberculin syringes are used to measure very small doses, one must be aware of the problem of inadvertent overadministration of digoxin. The syringe should not be flushed with the parenteral solution after its contents are expelled into an indwelling vascular catheter.
Slow infusion of LANOXIN Injection is preferable to bolus administration. Rapid infusion of digitalis glycosides has been shown to cause systemic and coronary arteriolar constriction, which may be clinically undesirable. Caution is thus advised and LANOXIN Injection should probably be administered over a period of 5 minutes or longer. Mixing of LANOXIN Injection with other drugs in the same container or simultaneous administration in the same intravenous line is not recommended.
In selecting a dose of digoxin, the following factors must be considered:
The body weight of the patient. Doses should be calculated based upon lean (i.e., ideal) body weight. The patient’s renal function, preferably evaluated on the basis of estimated creatinine clearance. The patient’s age. Infants and children require different doses of digoxin than adults. Also, advanced age may be indicative of diminished renal function even in patients with normal serum creatinine concentration (i.e., below 1.5 mg/dL). Concomitant disease states, concurrent medications, or other factors likely to alter the pharmacokinetic or pharmacodynamic profile of digoxin (see PRECAUTIONS). Serum Digoxin ConcentrationsIn general, the dose of digoxin used should be determined on clinical grounds. However, measurement of serum digoxin concentrations can be helpful to the clinician in determining the adequacy of digoxin therapy and in assigning certain probabilities to the likelihood of digoxin intoxication. About two-thirds of adults considered adequately digitalized (without evidence of toxicity) have serum digoxin concentrations ranging from 0.8 to 2.0 ng/mL (lower serum trough concentrations of 0.5 to 1 ng/mL may be appropriate in some adult patients, see Maintenance Dosing). However, digoxin may produce clinical benefits even at serum concentrations below this range. About two-thirds of adult patients with clinical toxicity have serum digoxin concentrations greater than 2.0 ng/mL. However, since one-third of patients with clinical toxicity have concentrations less than 2.0 ng/mL, values below 2.0 ng/mL do not rule out the possibility that a certain sign or symptom is related to digoxin therapy. Rarely, there are patients who are unable to tolerate digoxin at serum concentrations below 0.8 ng/mL. Consequently, the serum concentration of digoxin should always be interpreted in the overall clinical context, and an isolated measurement should not be used alone as the basis for increasing or decreasing the dose of the drug.
To allow adequate time for equilibration of digoxin between serum and tissue, sampling of serum concentrations should be done just before the next scheduled dose of the drug. If this is not possible, sampling should be done at least 6 to 8 hours after the last dose, regardless of the route of administration or the formulation used. On a once-daily dosing schedule, the concentration of digoxin will be 10% to 25% lower when sampled at 24 versus 8 hours, depending upon the patient’s renal function. On a twice-daily dosing schedule, there will be only minor differences in serum digoxin concentrations whether sampling is done at 8 or 12 hours after a dose.
If a discrepancy exists between the reported serum concentration and the observed clinical response, the clinician should consider the following possibilities:
Analytical problems in the assay procedure. Inappropriate serum sampling time. Administration of a digitalis glycoside other than digoxin. Conditions (described in WARNINGS and PRECAUTIONS) causing an alteration in the sensitivity of the patient to digoxin. Serum digoxin concentration may decrease acutely during periods of exercise without any associated change in clinical efficacy due to increased binding of digoxin to skeletal muscle. Heart Failure AdultsDigitalization may be accomplished by either of 2 general approaches that vary in dosage and frequency of administration, but reach the same endpoint in terms of total amount of digoxin accumulated in the body.
If rapid digitalization is considered medically appropriate, it may be achieved by administering a loading dose based upon projected peak digoxin body stores. Maintenance dose can be calculated as a percentage of the loading dose. More gradual digitalization may be obtained by beginning an appropriate maintenance dose, thus allowing digoxin body stores to accumulate slowly. Steady-state serum digoxin concentrations will be achieved in approximately 5 half-lives of the drug for the individual patient. Depending upon the patient’s renal function, this will take between 1 and 3 weeks.
Rapid Digitalization With a Loading DoseLANOXIN Injection is frequently used to achieve rapid digitalization, with conversion to LANOXIN Tablets for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see Table 1, CLINICAL PHARMACOLOGY: Pharmacokinetics and dosing Table 5).
Intramuscular injection of digoxin is extremely painful and offers no advantages unless other routes of administration are contraindicated.
Peak digoxin body stores of 8 to 12 mcg/kg should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. Because of altered digoxin distribution and elimination, projected peak body stores for patients with renal insufficiency should be conservative (i.e., 6 to 10 mcg/kg) (see PRECAUTIONS).
The loading dose should be administered in several portions, with roughly half the total given as the first dose. Additional fractions of this planned total dose may be given at 6- to 8-hour intervals, with careful assessment of clinical response before each additional dose. If the patient’s clinical response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.
A single initial intravenous dose of 400 to 600 mcg (0.4 to 0.6 mg) of LANOXIN Injection usually produces a detectable effect in 5 to 30 minutes that becomes maximal in 1 to 4 hours. Additional doses of 100 to 300 mcg (0.1 to 0.3 mg) may be given cautiously at 6- to 8-hour intervals until clinical evidence of an adequate effect is noted. The usual amount of LANOXIN Injection that a 70-kg patient requires to achieve 8- to 12-mcg/kg peak body stores is 600 to 1,000 mcg (0.6 to 1.0 mg).
Maintenance DosingThe doses of oral digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg (0.125 to 0.5 mg) once daily. In these studies, the digoxin dose has been generally titrated according to the patient’s age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg (0.25 mg) once daily in patients under age 70 with good renal function, at a dose of 125 mcg (0.125 mg) once daily in patients over age 70 or with impaired renal function, and at a dose of 62.5 mcg (0.0625 mg) in patients with marked renal impairment. Doses may be increased every 2 weeks according to clinical response.
In a subset of approximately 1,800 patients enrolled in the DIG trial (wherein dosing was based on an algorithm similar to that in Table 5) the mean (± SD) serum digoxin concentrations at 1 month and 12 months were 1.01 ± 0.47 ng/mL and 0.97 ± 0.43 ng/mL, respectively. There are no rigid guidelines as to the range of serum concentrations that are most efficacious. Several post hoc analyses of heart failure patients in the DIG trial suggest that the optimal trough digoxin serum level may be 0.5 ng/mL to 1 ng/mL.
The maintenance dose should be based upon the percentage of the peak body stores lost each day through elimination. The following formula has had wide clinical use:
Maintenance Dose = Peak Body Stores (i.e., Loading Dose) x % Daily Loss/100
Where: % Daily Loss = 14 + Ccr/5
(Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area.)
Table 5 provides average daily maintenance dose requirements of LANOXIN Injection for patients with heart failure based upon lean body weight and renal function:
Table 5. Usual Daily Maintenance Dose Requirements (mcg) of LANOXIN Injection for Estimated Peak Body Stores of 10 mcg/kgaCorrected Ccr
(mL/min per 70 kg)b
Lean Body Weight
Number of Days
kg
50
60
70
80
90
100
Before Steady State Achievedc
lb
110
132
154
176
198
220
0
75d
75
100
100
125
150
22
10
75
100
100
125
150
150
19
20
100
100
125
150
150
175
16
30
100
125
150
150
175
200
14
40
100
125
150
175
200
225
13
50
125
150
175
200
225
250
12
60
125
150
175
200
225
250
11
70
150
175
200
225
250
275
10
80
150
175
200
250
275
300
9
90
150
200
225
250
300
325
8
100
175
200
250
275
300
350
7
a Daily maintenance doses have been rounded to the nearest 25-mcg increment.
b Ccr is creatinine clearance, corrected to 70-kg body weight or 1.73 m2 body surface area. For adults, if only serum creatinine concentrations (Scr) are available, a Ccr (corrected to 70 kg body weight) may be estimated in men as (140 - Age)/Scr. For women, this result should be multiplied by 0.85. Note: This equation cannot be used for estimating creatinine clearance in infants or children.
c If no loading dose administered.
d 75mcg = 0.075 mg.
Example: Based on the above table, a patient in heart failure with an estimated lean body weight of 70 kg and a Ccr of 60 mL/min should be given a dose of 175 mcg (0.175 mg) daily of LANOXIN Injection. If no loading dose is administered, steady-state serum concentrations in this patient should be anticipated at approximately 11 days.
Infants and ChildrenSee the full prescribing information for LANOXIN Injection Pediatric for specific recommendations.
It cannot be overemphasized that dosage guidelines provided are based upon average patient response and substantial individual variation can be expected. Accordingly, ultimate dosage selection must be based upon clinical assessment of the patient.
Atrial FibrillationPeak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects. Data are not available to establish the appropriate resting or exercise target rates that should be achieved.
Dosage Adjustment When Changing PreparationsThe difference in bioavailability between LANOXIN Injection or LANOXIN Tablets must be considered when changing patients from one dosage form to the other.
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Pd-rx Pharmaceuticals, Inc.
Lanoxin | Pd-rx Pharmaceuticals, Inc.
GeneralRecommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications. In selecting a dose of digoxin, the following factors must be considered:
The body weight of the patient. Doses should be calculated based upon lean (i.e., ideal) body weight. The patient’s renal function, preferably evaluated on the basis of estimated creatinine clearance. The patient’s age. Infants and children require different doses of digoxin than adults. Also, advanced age may be indicative of diminished renal function even in patients with normal serum creatinine concentration (i.e., below 1.5 mg/dL). Concomitant disease states, concurrent medications, or other factors likely to alter the pharmacokinetic or pharmacodynamic profile of digoxin (see PRECAUTIONS). Serum Digoxin ConcentrationsIn general, the dose of digoxin used should be determined on clinical grounds. However, measurement of serum digoxin concentrations can be helpful to the clinician in determining the adequacy of digoxin therapy and in assigning certain probabilities to the likelihood of digoxin intoxication. About two-thirds of adults considered adequately digitalized (without evidence of toxicity) have serum digoxin concentrations ranging from 0.8 to 2.0 ng/mL (lower serum trough concentrations of 0.5 to 1 ng/mL may be appropriate in some adult patients, see Maintenance Dosing). However, digoxin may produce clinical benefits even at serum concentrations below this range. About two-thirds of adult patients with clinical toxicity have serum digoxin concentrations greater than 2.0 ng/mL. However, since one-third of patients with clinical toxicity have concentrations less than 2.0 ng/mL, values below 2.0 ng/mL do not rule out the possibility that a certain sign or symptom is related to digoxin therapy. Rarely, there are patients who are unable to tolerate digoxin at serum concentrations below 0.8 ng/mL. Consequently, the serum concentration of digoxin should always be interpreted in the overall clinical context, and an isolated measurement should not be used alone as the basis for increasing or decreasing the dose of the drug.
To allow adequate time for equilibration of digoxin between serum and tissue, sampling of serum concentrations should be done just before the next scheduled dose of the drug. If this is not possible, sampling should be done at least 6 to 8 hours after the last dose, regardless of the route of administration or the formulation used. On a once-daily dosing schedule, the concentration of digoxin will be 10% to 25% lower when sampled at 24 versus 8 hours, depending upon the patient’s renal function. On a twice-daily dosing schedule, there will be only minor differences in serum digoxin concentrations whether sampling is done at 8 or 12 hours after a dose.
If a discrepancy exists between the reported serum concentration and the observed clinical response, the clinician should consider the following possibilities:
Analytical problems in the assay procedure. Inappropriate serum sampling time. Administration of a digitalis glycoside other than digoxin. Conditions (described in WARNINGS and PRECAUTIONS) causing an alteration in the sensitivity of the patient to digoxin. Serum digoxin concentration may decrease acutely during periods of exercise without any associated change in clinical efficacy due to increased binding of digoxin to skeletal muscle. Heart Failure AdultsDigitalization may be accomplished by either of 2 general approaches that vary in dosage and frequency of administration, but reach the same endpoint in terms of total amount of digoxin accumulated in the body.
If rapid digitalization is considered medically appropriate, it may be achieved by administering a loading dose based upon projected peak digoxin body stores. Maintenance dose can be calculated as a percentage of the loading dose. More gradual digitalization may be obtained by beginning an appropriate maintenance dose, thus allowing digoxin body stores to accumulate slowly. Steady-state serum digoxin concentrations will be achieved in approximately 5 half-lives of the drug for the individual patient. Depending upon the patient’s renal function, this will take between 1 and 3 weeks. Rapid Digitalization With a Loading DosePeak digoxin body stores of 8 to 12 mcg/kg should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. Because of altered digoxin distribution and elimination, projected peak body stores for patients with renal insufficiency should be conservative (i.e., 6 to 10 mcg/kg) (see PRECAUTIONS).
The loading dose should be administered in several portions, with roughly half the total given as the first dose. Additional fractions of this planned total dose may be given at 6- to 8-hour intervals, with careful assessment of clinical response before each additional dose.
If the patient’s clinical response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.
A single initial dose of 500 to 750 mcg (0.5 to 0.75 mg) of LANOXIN Tablets usually produces a detectable effect in 0.5 to 2 hours that becomes maximal in 2 to 6 hours. Additional doses of 125 to 375 mcg (0.125 to 0.375 mg) may be given cautiously at 6- to 8-hour intervals until clinical evidence of an adequate effect is noted. The usual amount of LANOXIN Tablets that a 70-kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 750 to 1,250 mcg (0.75 to 1.25 mg).
LANOXIN Injection is frequently used to achieve rapid digitalization, with conversion to LANOXIN Tablets for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see Table 1, CLINICAL PHARMACOLOGY).
Maintenance DosingThe doses of digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg (0.125 to 0.5 mg) once daily. In these studies, the digoxin dose has been generally titrated according to the patient’s age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg (0.25 mg) once daily in patients under age 70 with good renal function, at a dose of 125 mcg (0.125 mg) once daily in patients over age 70 or with impaired renal function, and at a dose of 62.5 mcg (0.0625 mg) in patients with marked renal impairment. Doses may be increased every 2 weeks according to clinical response.
In a subset of approximately 1,800 patients enrolled in the DIG trial (wherein dosing was based on an algorithm similar to that in Table 5) the mean (± SD) serum digoxin concentrations at 1 month and 12 months were 1.01 ± 0.47 ng/mL and 0.97 ± 0.43 ng/mL, respectively. There are no rigid guidelines as to the range of serum concentrations that are most efficacious. Several post hoc analyses of heart failure patients in the DIG trial suggest that the optimal trough digoxin serum level may be 0.5 ng/mL to 1 ng/mL.
The maintenance dose should be based upon the percentage of the peak body stores lost each day through elimination. The following formula has had wide clinical use:
Maintenance Dose = Peak Body Stores (i.e., Loading Dose) x % Daily Loss/100
Where: % Daily Loss = 14 + Ccr/5
(Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area.)
Table 5 provides average daily maintenance dose requirements of LANOXIN Tablets for patients with heart failure based upon lean body weight and renal function:
Table 5. Usual Daily Maintenance Dose Requirements (mcg) of LANOXIN for Estimated Peak Body Stores of 10 mcg/kgCorrected Ccr
(mL/min per 70 kg)a
Lean Body Weight
Number of Days
kg
50
60
70
80
90
100
Before Steady
lb
110
132
154
176
198
220
State Achievedb
0
62.5c
125
125
125
187.5
187.5
22
10
125
125
125
187.5
187.5
187.5
19
20
125
125
187.5
187.5
187.5
250
16
30
125
187.5
187.5
187.5
250
250
14
40
125
187.5
187.5
250
250
250
13
50
187.5
187.5
250
250
250
250
12
60
187.5
187.5
250
250
250
375
11
70
187.5
250
250
250
250
375
10
80
187.5
250
250
250
375
375
9
90
187.5
250
250
250
375
500
8
100
250
250
250
375
375
500
7
a Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area. For adults, if only serum creatinine concentrations (Scr) are available, a Ccr (corrected to 70 kg body weight) may be estimated in men as (140 - Age)/Scr. For women, this result should be multiplied by 0.85. Note: This equation cannot be used for estimating creatinine clearance in infants or children.
b If no loading dose administered.
c 62.5 mcg = 0.0625 mg.
Example: Based on Table 5, a patient in heart failure with an estimated lean body weight of 70 kg and a Ccr of 60 mL/min should be given a dose of 250 mcg (0.25 mg) daily of LANOXIN Tablets, usually taken after the morning meal. If no loading dose is administered, steady-state serum concentrations in this patient should be anticipated at approximately 11 days.
Infants and ChildrenIn general, divided daily dosing is recommended for infants and young children (under age 10). In the newborn period, renal clearance of digoxin is diminished and suitable dosage adjustments must be observed. This is especially pronounced in the premature infant. Beyond the immediate newborn period, children generally require proportionally larger doses than adults on the basis of body weight or body surface area. Children over 10 years of age require adult dosages in proportion to their body weight. Some researchers have suggested that infants and young children tolerate slightly higher serum concentrations than do adults.
Daily maintenance doses for each age group are given in Table 6 and should provide therapeutic effects with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. These recommendations assume the presence of normal renal function:
Table 6. Daily Maintenance Doses in Children With Normal Renal FunctionAge
Daily Maintenance Dose (mcg/kg)
2 to 5 Years
10 to 15
5 to 10 Years
7 to 10
Over 10 Years
3 to 5
In children with renal disease, digoxin must be carefully titrated based upon clinical response.
It cannot be overemphasized that both the adult and pediatric dosage guidelines provided are based upon average patient response and substantial individual variation can be expected. Accordingly, ultimate dosage selection must be based upon clinical assessment of the patient.
Atrial FibrillationPeak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects. Data are not available to establish the appropriate resting or exercise target rates that should be achieved.
Dosage Adjustment When Changing PreparationsThe difference in bioavailability between LANOXIN Injection or LANOXIN Tablets must be considered when changing patients from one dosage form to the other.
-
Covis Pharmaceuticals Inc
Lanoxin | Covis Pharmaceuticals Inc
GeneralRecommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications.
Parenteral administration of digoxin should be used only when the need for rapid digitalization is urgent or when the drug cannot be taken orally. Intramuscular injection can lead to severe pain at the injection site, thus intravenous administration is preferred. If the drug must be administered by the intramuscular route, it should be injected deep into the muscle followed by massage. No more than 200 mcg (2 mL) should be injected into a single site.
LANOXIN Injection Pediatric can be administered undiluted or diluted with a 4-fold or greater volume of Sterile Water for Injection, 0.9% Sodium Chloride Injection, or 5% Dextrose Injection. The use of less than a 4-fold volume of diluent could lead to precipitation of the digoxin. Immediate use of the diluted product is recommended.
If tuberculin syringes are used to measure very small doses, one must be aware of the problem of inadvertent overadministration of digoxin. The syringe should not be flushed with the parenteral solution after its contents are expelled into an indwelling vascular catheter.
Slow infusion of LANOXIN Injection Pediatric is preferable to bolus administration. Rapid infusion of digitalis glycosides has been shown to cause systemic and coronary arteriolar constriction, which may be clinically undesirable. Caution is thus advised and LANOXIN Injection Pediatric should probably be administered over a period of 5 minutes or longer. Mixing of LANOXIN Injection Pediatric with other drugs in the same container or simultaneous administration in the same intravenous line is not recommended.
In selecting a dose of digoxin, the following factors must be considered:
The body weight of the patient. Doses should be calculated based upon lean (i.e., ideal) body weight. The patient’s renal function, preferably evaluated on the basis of estimated creatinine clearance. The patient’s age. Infants and children require different doses of digoxin than adults. Also, advanced age may be indicative of diminished renal function even in patients with normal serum creatinine concentration (i.e., below 1.5 mg/dL). Concomitant disease states, concurrent medications, or other factors likely to alter the pharmacokinetic or pharmacodynamic profile of digoxin (see PRECAUTIONS). Serum Digoxin ConcentrationsIn general, the dose of digoxin used should be determined on clinical grounds. However, measurement of serum digoxin concentrations can be helpful to the clinician in determining the adequacy of digoxin therapy and in assigning certain probabilities to the likelihood of digoxin intoxication. About two-thirds of adults considered adequately digitalized (without evidence of toxicity) have serum digoxin concentrations ranging from 0.8 to 2.0 ng/mL. However, digoxin may produce clinical benefits even at serum concentrations below this range. About two-thirds of adult patients with clinical toxicity have serum digoxin concentrations greater than 2.0 ng/mL. However, since one-third of patients with clinical toxicity have concentrations less than 2.0 ng/mL, values below 2.0 ng/mL do not rule out the possibility that a certain sign or symptom is related to digoxin therapy. Rarely, there are patients who are unable to tolerate digoxin at serum concentrations below 0.8 ng/mL. Consequently, the serum concentration of digoxin should always be interpreted in the overall clinical context, and an isolated measurement should not be used alone as the basis for increasing or decreasing the dose of the drug.
To allow adequate time for equilibration of digoxin between serum and tissue, sampling of serum concentrations should be done just before the next scheduled dose of the drug. If this is not possible, sampling should be done at least 6 to 8 hours after the last dose, regardless of the route of administration or the formulation used. On a once-daily dosing schedule, the concentration of digoxin will be 10% to 25% lower when sampled at 24 versus 8 hours, depending upon the patient’s renal function. On a twice-daily dosing schedule, there will be only minor differences in serum digoxin concentrations whether sampling is done at 8 or 12 hours after a dose.
If a discrepancy exists between the reported serum concentration and the observed clinical response, the clinician should consider the following possibilities:
Analytical problems in the assay procedure. Inappropriate serum sampling time. Administration of a digitalis glycoside other than digoxin. Conditions (described in WARNINGS and PRECAUTIONS) causing an alteration in the sensitivity of the patient to digoxin. Serum digoxin concentration may decrease acutely during periods of exercise without any associated change in clinical efficacy due to increased binding of digoxin to skeletal muscle. Heart Failure AdultsSee the full prescribing information for LANOXIN Injection for specific recommendations.
Infants and ChildrenIn general, divided daily dosing is recommended for infants and young children (under age 10). In the newborn period, renal clearance of digoxin is diminished and suitable dosage adjustments must be observed. This is especially pronounced in the premature infant. Beyond the immediate newborn period, children generally require proportionally larger doses than adults on the basis of body weight or body surface area. Children over 10 years of age require adult dosages in proportion to their body weight. Some researchers have suggested that infants and young children tolerate slightly higher serum concentrations than do adults.
Digitalization may be accomplished by either of two general approaches that vary in dosage and frequency of administration, but reach the same endpoint in terms of total amount of digoxin accumulated in the body.
If rapid digitalization is considered medically appropriate, it may be achieved by administering a loading dose based upon projected peak digoxin body stores. Maintenance dose can be calculated as a percentage of the loading dose. More gradual digitalization may be obtained by beginning an appropriate maintenance dose, thus allowing digoxin body stores to accumulate slowly. Steady-state serum digoxin concentrations will be achieved in approximately five half-lives of the drug for the individual patient. Depending upon the patient’s renal function, this will take between 1 and 3 weeks. Rapid Digitalization With a Loading DoseLANOXIN Injection Pediatric can be used to achieve rapid digitalization, with conversion to an oral formulation of LANOXIN for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see Table 1 in CLINICAL PHARMACOLOGY: Pharmacokinetics and dosing Table 5).
Intramuscular injection of digoxin is extremely painful and offers no advantages unless other routes of administration are contraindicated.
Peak digoxin body stores of 8 to 12 mcg/kg should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. Because of altered digoxin distribution and elimination, projected peak body stores for patients with renal insufficiency should be conservative (i.e., 6 to 10 mcg/kg) (see PRECAUTIONS).
Digitalizing and daily maintenance doses for each age group are given in Table 5 and should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. These recommendations assume the presence of normal renal function.
The loading dose should be administered in several portions, with roughly half the total given as the first dose. Additional fractions of this planned total dose may be given at 4- to 8-hour intervals, with careful assessment of clinical response before each additional dose. If the patient’s clinical response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.
Table 5. Usual Digitalizing and Maintenance Dosages for LANOXIN®Injection Pediatric in Children With Normal Renal Function Based on Lean Body WeightAge
IV Digitalizinga Dose (mcg/kg)
Daily IV Maintenance Doseb
(mcg/kg)
Premature
15 to 25
20% to 30% of the IV digitalizing dosec
Full-Term
20 to 30
1 to 24 Months
30 to 50
2 to 5 Years
25 to 35
25% to 35% of the IV digitalizing dosec
5 to 10 Years
15 to 30
Over 10 Years
8 to 12
a IV digitalizing doses are 80% of oral digitalizing doses.
b Divided daily dosing is recommended for children under 10 years of age.
c Projected or actual digitalizing dose providing clinical response.
In children with renal disease, digoxin dosing must be carefully titrated based on clinical response.
Gradual Digitalization With A Maintenance DoseMore gradual digitalization can also be accomplished by beginning an appropriate maintenance dose. The range of percentages provided in Table 5 can be used in calculating this dose for patients with normal renal function.
It cannot be overemphasized that these pediatric dosage guidelines are based upon average patient response and substantial individual variation can be expected. Accordingly, ultimate dosage selection must be based upon clinical assessment of the patient.
Atrial FibrillationPeak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects. Data are not available to establish the appropriate resting or exercise target rates that should be achieved.
Dosage Adjustment When Changing PreparationsThe differences in bioavailability between injectable LANOXIN or LANOXIN Tablets must be considered when changing patients from one dosage form to another.
-
Remedyrepack Inc.
Lanoxin | Remedyrepack Inc.
In selecting a LANOXIN dosing regimen, it is important to consider factors that affect digoxin blood levels (e.g., body weight, age, renal function, concomitant drugs) since toxic levels of digoxin are only slightly higher than therapeutic levels. Dosing can be either initiated with a loading dose followed by maintenance dosing if rapid titration is desired or initiated with maintenance dosing without a loading dose.
Consider interruption or reduction in digoxin dose prior to electrical cardioversion [see Warnings and Precautions (5.6)].
Use digoxin solution to obtain the appropriate dose in infants, young pediatric patients, or patients with very low body weight.
For adults and pediatric patients if a loading dosage is to be given, administer half the total loading dose initially, then ¼ the loading dose every 4 to 8 hours twice, with careful assessment of clinical response and toxicity before each dose. The recommended loading dose is displayed in Table 1.
Table 1. Recommended LANOXIN Oral Loading Dose Age Oral Loading Dose, mcg/kg 5 to 10 years 20 - 45 Adults and pediatric patients over 10 years 10 - 15 mcg = microgramsThe maintenance dose is based on the lean body weight, renal function, age, and concomitant products [see Drug Interactions (7.1, 7.2, 7.3)].
The recommended starting maintenance dosage in adults and pediatric patients over 10 years old is displayed in Table 2. Doses may be increased every 2 weeks according to clinical response, serum drug levels, and toxicity.
Table 2. Recommended Starting LANOXIN Maintenance Dosage in Adults and Pediatric Patients Over 10 Years Old Age Oral Maintenance Dose, mcg/kg/day
(given once daily) Adults and pediatric patients over 10 years 3.4 – 5.1 mcg = microgramsTable 3 displays the recommended (once daily) maintenance dose of LANOXIN in pediatric patients over 10 years old and adult patients according to lean body weight and renal function. The doses are based on studies in adult patients with heart failure. Alternatively, the maintenance dose may be estimated by the following formula (peak body stores lost each day through elimination):
Total Maintenance Dose = Loading Dose (i.e., Peak Body Stores) x % Daily Loss/100
(% Daily Loss = 14 + Creatinine clearance/5)Reduce the dose of LANOXIN in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.
Table 3. Recommended Maintenance Dose (in micrograms given once daily) of LANOXIN in Pediatric Patients Over 10 Years Old and Adults by Lean Body Weight and by Renal Functiona Corrected
Creatinine
Clearanceb Number of
Days Before
Steady State
Achievedc Lean Body Weightd kg 40 50 60 70 80 90 100 lb 88 110 132 154 176 198 220 10 mL/min 62.5* 125 125 187.5 187.5 187.5 250 19 20 mL/min 125 125 125 187.5 187.5 250 250 16 30 mL/min 125 125 187.5 187.5 250 250 312.5 14 40 mL/min 125 187.5 187.5 250 250 312.5 312.5 13 50 mL/min 125 187.5 187.5 250 250 312.5 312.5 12 60 mL/min 125 187.5 250 250 312.5 312.5 375 11 70 mL/min 187.5 187.5 250 250 312.5 375 375 10 80 mL/min 187.5 187.5 250 312.5 312.5 375 437.5 9 90 mL/min 187.5 250 250 312.5 375 437.5 437.5 8 100 mL/min 187.5 250 312.5 312.5 375 437.5 500 7 a Doses are rounded to the nearest dose possible using whole and/or half LANOXIN tablets. Recommended doses approximately 30 percent lower than the calculated dose are designated with an *. Monitor digoxin levels in patients receiving these initial doses and increase dose if needed.
b For adults, creatinine clearance was corrected to 70-kg body weight or 1.73 m2 body surface area. If only serum creatinine concentrations (Scr) are available, a corrected Ccr may be estimated in men as (140 – Age)/Scr. For women, this result should be multiplied by 0.85.
For pediatric patients, the modified Schwartz equation may be used. The formula is based on height in cm and Scr in mg/dL where k is a constant. Ccr is corrected to 1.73 m2 body surface area. During the first year of life, the value of k is 0.33 for pre-term babies and 0.45 for term infants. The k is 0.55 for pediatric patients and adolescent girls and 0.7 for adolescent boys.
GFR (mL/min/1.73 m2) = (k x Height)/Scr
c If no loading dose administered.
d The doses listed assume average body composition.The starting maintenance dose for heart failure in pediatric patients less than 10 years old is based on the lean body weight, renal function, age, and concomitant products [see Drug Interactions (7.1, 7.2, 7.3)]. The recommended starting maintenance dose for pediatric patients between 5 and 10 years old with normal renal function is displayed in Table 4.
Table 4. Recommended Starting LANOXIN Maintenance Dosage in Pediatric Patients Between 5 and 10 Years Old Age Daily Oral
Maintenance Dose,
mcg/kg/day Dose Regimen,
mcg/kg/dose 5 to 10 years 6.4 – 12.9 3.2 – 6.4 Twice dailyThe recommended maintenance dose (to be given twice daily) is presented in Table 5.
Table 5. Recommended Maintenance Dose (in micrograms given twice daily) of LANOXIN in Pediatric Patients <10 Years of Agea Based upon Lean Body Weight and Renal Functiona,b Corrected
Creatinine
Clearancec Number of
Days Before
Steady State
Achievedd Lean Body Weight kg 20 30 40 50 60 lb 44 66 88 110 132 10 mL/min - 62.5 62.5* 125 125 19 20 mL/min 62.5 62.5 125 125 125 16 30 mL/min 62.5 62.5* 125 125 187.5 14 40 mL/min 62.5 62.5* 125 187.5 187.5 13 50 mL/min 62.5 125 125 187.5 187.5 12 60 mL/min 62.5 125 125 187.5 250 11 70 mL/min 62.5 125 187.5 187.5 250 10 80 mL/min 62.5* 125 187.5 187.5 250 9 90 mL/min 62.5* 125 187.5 250 250 8 100 mL/min 62.5* 125 187.5 250 312.5 7 a Recommended are doses to be given twice daily.
b The doses are rounded to the nearest dose possible using whole and/or half LANOXIN tablets. Recommended doses approximately 30 percent lower than the calculated dose are designated with an *. Monitor digoxin levels in patients receiving these initial doses and increase dose if needed.
c The modified Schwartz equation may be used to estimate creatinine clearance. See footnote b under Table 2.
d If no loading dose administered.Monitor for signs and symptoms of digoxin toxicity and clinical response. Adjust dose based on toxicity, efficacy, and blood levels.
Serum digoxin levels < 0.5 ng/mL have been associated with diminished efficacy, while levels above 2 ng/mL have been associated with increased toxicity without increased benefit.
Interpret the serum digoxin concentration in the overall clinical context, and do not use an isolated measurement of serum digoxin concentration as the basis for increasing or decreasing the LANOXIN dose. Serum digoxin concentrations may be falsely elevated by endogenous digoxin-like substances [see Drug Interactions (7.4)]. If the assay is sensitive to these substances, consider obtaining a baseline digoxin level before starting LANOXIN and correct post-treatment values by the reported baseline level.
Obtain serum digoxin concentrations just before the next scheduled LANOXIN dose or at least 6 hours after the last dose. The digoxin concentration is likely to be 10% to 25% lower when sampled right before the next dose (24 hours after dosing) compared to sampling 8 hours after dosing (using once-daily dosing). However, there will be only minor differences in digoxin concentrations using twice daily dosing whether sampling is done at 8 or 12 hours after a dose.
When switching from intravenous to oral digoxin formulations, make allowances for differences in bioavailability when calculating maintenance dosages (see Table 6).
Table 6. Comparison of the Systemic Availability and Equivalent Doses of Oral and Intravenous LANOXIN Absolute
Bioavailability Equivalent Doses (in micrograms) LANOXIN Tablets 60 - 80% 62.5 125 250 500 LANOXIN Intravenous Injection 100% 50 100 200 400 -
Glaxosmithkline Llc
Lanoxin | Glaxosmithkline Llc
GeneralRecommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications. In selecting a dose of digoxin, the following factors must be considered:
1. The body weight of the patient. Doses should be calculated based upon lean (i.e., ideal) body weight. 2. The patient’s renal function, preferably evaluated on the basis of estimated creatinine clearance. 3. The patient’s age. Infants and children require different doses of digoxin than adults. Also, advanced age may be indicative of diminished renal function even in patients with normal serum creatinine concentration (i.e., below 1.5 mg/dL). 4. Concomitant disease states, concurrent medications, or other factors likely to alter the pharmacokinetic or pharmacodynamic profile of digoxin (see PRECAUTIONS). Serum Digoxin ConcentrationsIn general, the dose of digoxin used should be determined on clinical grounds. However, measurement of serum digoxin concentrations can be helpful to the clinician in determining the adequacy of digoxin therapy and in assigning certain probabilities to the likelihood of digoxin intoxication. About two-thirds of adults considered adequately digitalized (without evidence of toxicity) have serum digoxin concentrations ranging from 0.8 to 2.0 ng/mL (lower serum trough concentrations of 0.5 to 1 ng/mL may be appropriate in some adult patients, see Maintenance Dosing). However, digoxin may produce clinical benefits even at serum concentrations below this range. About two-thirds of adult patients with clinical toxicity have serum digoxin concentrations greater than 2.0 ng/mL. However, since one-third of patients with clinical toxicity have concentrations less than 2.0 ng/mL, values below 2.0 ng/mL do not rule out the possibility that a certain sign or symptom is related to digoxin therapy. Rarely, there are patients who are unable to tolerate digoxin at serum concentrations below 0.8 ng/mL. Consequently, the serum concentration of digoxin should always be interpreted in the overall clinical context, and an isolated measurement should not be used alone as the basis for increasing or decreasing the dose of the drug.
To allow adequate time for equilibration of digoxin between serum and tissue, sampling of serum concentrations should be done just before the next scheduled dose of the drug. If this is not possible, sampling should be done at least 6 to 8 hours after the last dose, regardless of the route of administration or the formulation used. On a once-daily dosing schedule, the concentration of digoxin will be 10% to 25% lower when sampled at 24 versus 8 hours, depending upon the patient’s renal function. On a twice-daily dosing schedule, there will be only minor differences in serum digoxin concentrations whether sampling is done at 8 or 12 hours after a dose.
If a discrepancy exists between the reported serum concentration and the observed clinical response, the clinician should consider the following possibilities:
1. Analytical problems in the assay procedure. 2. Inappropriate serum sampling time. 3. Administration of a digitalis glycoside other than digoxin. 4. Conditions (described in WARNINGS and PRECAUTIONS) causing an alteration in the sensitivity of the patient to digoxin. 5. Serum digoxin concentration may decrease acutely during periods of exercise without any associated change in clinical efficacy due to increased binding of digoxin to skeletal muscle. Heart Failure AdultsDigitalization may be accomplished by either of 2 general approaches that vary in dosage and frequency of administration, but reach the same endpoint in terms of total amount of digoxin accumulated in the body.
1. If rapid digitalization is considered medically appropriate, it may be achieved by administering a loading dose based upon projected peak digoxin body stores. Maintenance dose can be calculated as a percentage of the loading dose. 2. More gradual digitalization may be obtained by beginning an appropriate maintenance dose, thus allowing digoxin body stores to accumulate slowly. Steady-state serum digoxin concentrations will be achieved in approximately 5 half-lives of the drug for the individual patient. Depending upon the patient’s renal function, this will take between 1 and 3 weeks. Rapid Digitalization With a Loading DosePeak digoxin body stores of 8 to 12 mcg/kg should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. Because of altered digoxin distribution and elimination, projected peak body stores for patients with renal insufficiency should be conservative (i.e., 6 to 10 mcg/kg) (see PRECAUTIONS).
The loading dose should be administered in several portions, with roughly half the total given as the first dose. Additional fractions of this planned total dose may be given at 6- to 8-hour intervals, with careful assessment of clinical response before each additional dose.
If the patient’s clinical response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.
A single initial dose of 500 to 750 mcg (0.5 to 0.75 mg) of LANOXIN Tablets usually produces a detectable effect in 0.5 to 2 hours that becomes maximal in 2 to 6 hours. Additional doses of 125 to 375 mcg (0.125 to 0.375 mg) may be given cautiously at 6- to 8-hour intervals until clinical evidence of an adequate effect is noted. The usual amount of LANOXIN Tablets that a 70-kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 750 to 1,250 mcg (0.75 to 1.25 mg).
LANOXIN Injection is frequently used to achieve rapid digitalization, with conversion to LANOXIN Tablets for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see Table 1, CLINICAL PHARMACOLOGY).
Maintenance DosingThe doses of digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg (0.125 to 0.5 mg) once daily. In these studies, the digoxin dose has been generally titrated according to the patient’s age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg (0.25 mg) once daily in patients under age 70 with good renal function, at a dose of 125 mcg (0.125 mg) once daily in patients over age 70 or with impaired renal function, and at a dose of 62.5 mcg (0.0625 mg) in patients with marked renal impairment. Doses may be increased every 2 weeks according to clinical response.
In a subset of approximately 1,800 patients enrolled in the DIG trial (wherein dosing was based on an algorithm similar to that in Table 5) the mean (± SD) serum digoxin concentrations at 1 month and 12 months were 1.01 ± 0.47 ng/mL and 0.97 ± 0.43 ng/mL, respectively. There are no rigid guidelines as to the range of serum concentrations that are most efficacious. Several post hoc analyses of heart failure patients in the DIG trial suggest that the optimal trough digoxin serum level may be 0.5 ng/mL to 1 ng/mL.
The maintenance dose should be based upon the percentage of the peak body stores lost each day through elimination. The following formula has had wide clinical use:
Maintenance Dose = Peak Body Stores (i.e., Loading Dose) x % Daily Loss/100
Where: % Daily Loss = 14 + Ccr/5
(Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area.)
Table 5 provides average daily maintenance dose requirements of LANOXIN Tablets for patients with heart failure based upon lean body weight and renal function:
Table 5. Usual Daily Maintenance Dose Requirements (mcg) of LANOXIN for Estimated Peak Body Stores of 10 mcg/kgCorrected Ccr
(mL/min per 70 kg)a
Lean Body Weight
Number of Days
kg
50
60
70
80
90
100
Before Steady
lb
110
132
154
176
198
220
State Achievedb
0
62.5c
125
125
125
187.5
187.5
22
10
125
125
125
187.5
187.5
187.5
19
20
125
125
187.5
187.5
187.5
250
16
30
125
187.5
187.5
187.5
250
250
14
40
125
187.5
187.5
250
250
250
13
50
187.5
187.5
250
250
250
250
12
60
187.5
187.5
250
250
250
375
11
70
187.5
250
250
250
250
375
10
80
187.5
250
250
250
375
375
9
90
187.5
250
250
250
375
500
8
100
250
250
250
375
375
500
7
a Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area. For adults, if only serum creatinine concentrations (Scr) are available, a Ccr (corrected to 70 kg body weight) may be estimated in men as (140 - Age)/Scr. For women, this result should be multiplied by 0.85. Note: This equation cannot be used for estimating creatinine clearance in infants or children.
b If no loading dose administered.
c 62.5 mcg = 0.0625 mg.
Example: Based on Table 5, a patient in heart failure with an estimated lean body weight of 70 kg and a Ccr of 60 mL/min should be given a dose of 250 mcg (0.25 mg) daily of LANOXIN Tablets, usually taken after the morning meal. If no loading dose is administered, steady-state serum concentrations in this patient should be anticipated at approximately 11 days.
Infants and ChildrenIn general, divided daily dosing is recommended for infants and young children (under age 10). In the newborn period, renal clearance of digoxin is diminished and suitable dosage adjustments must be observed. This is especially pronounced in the premature infant. Beyond the immediate newborn period, children generally require proportionally larger doses than adults on the basis of body weight or body surface area. Children over 10 years of age require adult dosages in proportion to their body weight. Some researchers have suggested that infants and young children tolerate slightly higher serum concentrations than do adults.
Daily maintenance doses for each age group are given in Table 6 and should provide therapeutic effects with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. These recommendations assume the presence of normal renal function:
Table 6. Daily Maintenance Doses in Children With Normal Renal FunctionAge
Daily Maintenance Dose (mcg/kg)
2 to 5 Years
10 to 15
5 to 10 Years
7 to 10
Over 10 Years
3 to 5
In children with renal disease, digoxin must be carefully titrated based upon clinical response.
It cannot be overemphasized that both the adult and pediatric dosage guidelines provided are based upon average patient response and substantial individual variation can be expected. Accordingly, ultimate dosage selection must be based upon clinical assessment of the patient.
Atrial FibrillationPeak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects. Data are not available to establish the appropriate resting or exercise target rates that should be achieved.
Dosage Adjustment When Changing PreparationsThe difference in bioavailability between LANOXIN Injection or LANOXIN Tablets must be considered when changing patients from one dosage form to the other.
-
Covis Pharmaceuticals Inc
Lanoxin | Covis Pharmaceuticals, Inc.
2.1 Important Dosing and Administration InformationIn selecting a LANOXIN dosing regimen, it is important to consider factors that affect digoxin blood levels (e.g., body weight, age, renal function, concomitant drugs) since toxic levels of digoxin are only slightly higher than therapeutic levels. Dosing can be either initiated with a loading dose followed by maintenance dosing if rapid titration is desired or initiated with maintenance dosing without a loading dose.
Parenteral administration of digoxin should be used only when the need for rapid digitalization is urgent or when the drug cannot be taken orally. Intramuscular injection can lead to severe pain at the injection site, thus intravenous administration is preferred. If the drug must be administered by the intramuscular route, it should be injected deep into the muscle followed by massage. For adults, no more than 500 mcg of LANOXIN Injection should be injected into a single site. For pediatric patients, no more than 200 mcg of LANOXIN Injection Pediatric should be injected into a single site.
Administer the dose over a period of 5 minutes or longer and avoid bolus administration to prevent systemic and coronary vasoconstriction. Mixing of LANOXIN Injection and Injection Pediatric with other drugs in the same container or simultaneous administration in the same intravenous line is not recommended.
LANOXIN Injection and Injection Pediatric can be administered undiluted or diluted with a 4-fold or greater volume of Sterile Water for Injection, 0.9% Sodium Chloride Injection, or 5% Dextrose Injection. The use of less than a 4-fold volume of diluent could lead to precipitation of the digoxin. Immediate use of the diluted product is recommended.
If tuberculin syringes are used to measure very small doses do not flush with the parenteral solution after its contents are expelled into an indwelling vascular catheter to avoid overadministration of digoxin.
Consider interruption or reduction in LANOXIN dose prior to electrical cardioversion [see Warnings and Precautions (5.4)].
2.2 Loading Dosing Regimen in Adults and Pediatric Patients Table 1. Recommended LANOXIN Injection Loading Dose mcg = microgramAge
Total IV Loading Dose (mcg/kg)
Administer half the total loading dose initially,
then ¼ the loading dose every 6-8 hours twicePremature
15-25
Full-Term
20-30
1-24 Months
30-50
2-5 Years
25-35
5-10 Years
15-30
Adults and pediatric patients over 10 years
8-12
2.3 Maintenance Dosing in Adults and Pediatric Patients Over 10 Years OldThe maintenance dose is based on lean body weight, renal function, age, and concomitant products [see Clinical Pharmacology (12.3)].
The recommended starting maintenance doses in adults and pediatric patients over 10 years old with normal renal function are given in Table 2. Doses may be increased every 2 weeks according to clinical response, serum drug levels, and toxicity.
Table 2. Recommended Starting LANOXIN Injection Maintenance Dosage in Adults and Pediatric Patients Over 10 Years Old mcg = microgramAge
Total Intravenous Maintenance Dose,
mcg/kg/day
(given once daily)Adults and pediatric patients over 10 years
2.4-3.6
Table 3 provides the recommended (once daily) maintenance dose for adults and pediatric patients over 10 years old (to be given once daily) according to lean body weight and renal function. The doses are based on studies in adult patients with heart failure. Alternatively, the maintenance dose may be estimated by the following formula (peak body stores lost each day through elimination):
Total Maintenance Dose = Loading Dose (i.e., Peak Body Stores) x % Daily Loss/100
(% Daily Loss = 14 + Creatinine clearance/5)Reduce the dose of LANOXIN in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.
Table 3. Recommended Maintenance Dose (in micrograms given once daily) of LANOXIN Injection in Pediatric Patients Over 10 Years Old and Adults by Lean Body Weight and by Renal Function a For adults, creatinine clearance was corrected to 70-kg body weight or 1.73 m2 body surface area. If only serum creatinine concentrations (Scr) are available, a corrected Ccr may be estimated in men as (140 – Age)/Scr. For women, this result should be multiplied by 0.85.
For pediatric patients, the modified Schwartz equation may be used. The formula is based on height in cm and Scr in mg/dL where k is a constant. Ccr is corrected to 1.73 m2 body surface area. During the first year of life, the value of k is 0.33 for pre-term babies and 0.45 for term infants. The k is 0.55 for pediatric patients and adolescent girls and 0.7 for adolescent boys.
GFR (mL/min/1.73 m2) = (k x Height)/Scr
b If no loading dose administered
c The doses listed assume average body composition.Corrected
Creatinine ClearanceaLean Body Weightc
Number of Days
Before Steady
State Achievedbkg
40
50
60
70
80
90
100
10 mL/min
64
80
96
112
128
144
160
19
20 mL/min
72
90
108
126
144
162
180
16
30 mL/min
80
100
120
140
160
180
200
14
40 mL/min
88
110
132
154
176
198
220
13
50 mL/min
96
120
144
168
192
216
240
12
60 mL/min
104
130
156
182
208
234
260
11
70 mL/min
112
140
168
196
224
252
280
10
80 mL/min
120
150
180
210
240
270
300
9
90 mL/min
128
160
192
224
256
288
320
8
100 mL/min
136
170
204
238
272
306
340
7
2.4 Maintenance Dosing in Pediatric Patients Less Than 10 Years OldThe starting maintenance dose for heart failure in pediatric patients less than 10 years old is based on lean body weight, renal function, age, and concomitant products [see Clinical Pharmacology (12.3)]. The recommended starting maintenance doses for pediatric patients are given in Table 4. These recommendations assume the presence of normal renal function.
Table 4. Recommended Starting LANOXIN Injection Maintenance Dosage in Pediatric Patients Less Than 10 Years Old mcg = microgramAge
Dose Regimen,
mcg/kg/dose
(given TWICE daily)Premature
1.9-3.1
Full-Term
3.0-4.5
1-24 Months
4.5-7.5
2-5 Years
3.8-5.3
5-10 Years
2.3-4.5
Table 5 provides average daily maintenance dose requirements for pediatric patients less than 10 years old (to be given twice daily) with heart failure based on age, lean body weight, and renal function.
Table 5. Recommended Maintenance Dose (in micrograms given TWICE daily) of LANOXIN Injection in Pediatric Patients Less Than 10 Years of Agea Based upon Lean Body Weight and Renal Functiona a Recommended are doses to be given twice daily.
b The modified Schwartz equation may be used to estimate creatinine clearance. See footnote a under Table 3.
c If no loading dose administered.Corrected
Creatinine ClearancebLean Body Weight
Number of Days
Before Steady
State Achievedckg
5
10
20
30
40
50
60
10 mL/min
8
16
32
48
64
80
96
19
20 mL/min
9
18
36
54
72
90
108
16
30 mL/min
10
20
40
60
80
100
120
14
40 mL/min
11
22
44
66
88
110
132
13
50 mL/min
12
24
48
72
96
120
144
12
60 mL/min
13
26
52
78
104
130
156
11
70 mL/min
14
28
56
84
112
140
168
10
80 mL/min
15
30
60
90
120
150
180
9
90 mL/min
16
32
64
96
128
160
192
8
100 mL/min
17
34
68
102
136
170
204
7
2.5 Monitoring to Assess Safety, Efficacy, and Therapeutic Blood LevelsMonitor for signs and symptoms of digoxin toxicity and clinical response. Adjust dose based on toxicity, efficacy, and blood levels.
Serum digoxin levels less than 0.5 ng/mL have been associated with diminished efficacy, while levels above 2 ng/mL have been associated with increased toxicity without increased benefit.
Interpret the serum digoxin concentration in the overall clinical context, and do not use an isolated measurement of serum digoxin concentration as the basis for increasing or decreasing the LANOXIN dose. Serum digoxin concentrations may be falsely elevated by endogenous digoxin-like substances [see Drug Interactions (7.4)]. If the assay is sensitive to these substances, consider obtaining a baseline digoxin level before starting LANOXIN and correct post-treatment values by the reported baseline level.
Obtain serum digoxin concentrations just before the next scheduled LANOXIN dose or at least 6 hours after the last dose. The digoxin concentration is likely to be 10-25% lower when sampled right before the next dose (24 hours after dosing) compared to sampling 8 hours after dosing (using once-daily dosing). However, there will be only minor differences in digoxin concentrations using twice daily dosing whether sampling is done at 8 or 12 hours after a dose.
2.6 Switching from Intravenous Digoxin to Oral DigoxinWhen switching from intravenous to oral digoxin formulations, make allowances for differences in bioavailability when calculating maintenance dosages (see Table 6).
Table 6. Comparison of the Systemic Availability and Equivalent Doses of Oral and Intravenous LANOXINAbsolute Bioavailability
Equivalent Doses (mcg)
LANOXIN Tablets
60-80%
62.5
125
250
500
LANOXIN Intravenous Injection
100%
50
100
200
400
-
Cardinal Health
Lanoxin | Cardinal Health
GeneralRecommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications. In selecting a dose of digoxin, the following factors must be considered:
The body weight of the patient. Doses should be calculated based upon lean (i.e., ideal) body weight. The patient’s renal function, preferably evaluated on the basis of estimated creatinine clearance. The patient’s age. Infants and children require different doses of digoxin than adults. Also, advanced age may be indicative of diminished renal function even in patients with normal serum creatinine concentration (i.e., below 1.5 mg/dL). Concomitant disease states, concurrent medications, or other factors likely to alter the pharmacokinetic or pharmacodynamic profile of digoxin (see PRECAUTIONS). Serum Digoxin ConcentrationsIn general, the dose of digoxin used should be determined on clinical grounds. However, measurement of serum digoxin concentrations can be helpful to the clinician in determining the adequacy of digoxin therapy and in assigning certain probabilities to the likelihood of digoxin intoxication. About two-thirds of adults considered adequately digitalized (without evidence of toxicity) have serum digoxin concentrations ranging from 0.8 to 2.0 ng/mL (lower serum trough concentrations of 0.5 to 1 ng/mL may be appropriate in some adult patients, see Maintenance Dosing). However, digoxin may produce clinical benefits even at serum concentrations below this range. About two-thirds of adult patients with clinical toxicity have serum digoxin concentrations greater than 2.0 ng/mL. However, since one-third of patients with clinical toxicity have concentrations less than 2.0 ng/mL, values below 2.0 ng/mL do not rule out the possibility that a certain sign or symptom is related to digoxin therapy. Rarely, there are patients who are unable to tolerate digoxin at serum concentrations below 0.8 ng/mL. Consequently, the serum concentration of digoxin should always be interpreted in the overall clinical context, and an isolated measurement should not be used alone as the basis for increasing or decreasing the dose of the drug.
To allow adequate time for equilibration of digoxin between serum and tissue, sampling of serum concentrations should be done just before the next scheduled dose of the drug. If this is not possible, sampling should be done at least 6 to 8 hours after the last dose, regardless of the route of administration or the formulation used. On a once-daily dosing schedule, the concentration of digoxin will be 10% to 25% lower when sampled at 24 versus 8 hours, depending upon the patient’s renal function. On a twice-daily dosing schedule, there will be only minor differences in serum digoxin concentrations whether sampling is done at 8 or 12 hours after a dose.
If a discrepancy exists between the reported serum concentration and the observed clinical response, the clinician should consider the following possibilities:
Analytical problems in the assay procedure. Inappropriate serum sampling time. Administration of a digitalis glycoside other than digoxin. Conditions (described in WARNINGS and PRECAUTIONS) causing an alteration in the sensitivity of the patient to digoxin. Serum digoxin concentration may decrease acutely during periods of exercise without any associated change in clinical efficacy due to increased binding of digoxin to skeletal muscle. Heart Failure AdultsDigitalization may be accomplished by either of 2 general approaches that vary in dosage and frequency of administration, but reach the same endpoint in terms of total amount of digoxin accumulated in the body.
If rapid digitalization is considered medically appropriate, it may be achieved by administering a loading dose based upon projected peak digoxin body stores. Maintenance dose can be calculated as a percentage of the loading dose. More gradual digitalization may be obtained by beginning an appropriate maintenance dose, thus allowing digoxin body stores to accumulate slowly. Steady-state serum digoxin concentrations will be achieved in approximately 5 half-lives of the drug for the individual patient. Depending upon the patient’s renal function, this will take between 1 and 3 weeks. Rapid Digitalization With a Loading DosePeak digoxin body stores of 8 to 12 mcg/kg should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. Because of altered digoxin distribution and elimination, projected peak body stores for patients with renal insufficiency should be conservative (i.e., 6 to 10 mcg/kg) (see PRECAUTIONS).
The loading dose should be administered in several portions, with roughly half the total given as the first dose. Additional fractions of this planned total dose may be given at 6- to 8-hour intervals, with careful assessment of clinical response before each additional dose.
If the patient’s clinical response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.
A single initial dose of 500 to 750 mcg (0.5 to 0.75 mg) of LANOXIN Tablets usually produces a detectable effect in 0.5 to 2 hours that becomes maximal in 2 to 6 hours. Additional doses of 125 to 375 mcg (0.125 to 0.375 mg) may be given cautiously at 6- to 8-hour intervals until clinical evidence of an adequate effect is noted. The usual amount of LANOXIN Tablets that a 70-kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 750 to 1,250 mcg (0.75 to 1.25 mg).
LANOXIN Injection is frequently used to achieve rapid digitalization, with conversion to LANOXIN Tablets for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see Table 1, CLINICAL PHARMACOLOGY).
Maintenance DosingThe doses of digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg (0.125 to 0.5 mg) once daily. In these studies, the digoxin dose has been generally titrated according to the patient’s age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg (0.25 mg) once daily in patients under age 70 with good renal function, at a dose of 125 mcg (0.125 mg) once daily in patients over age 70 or with impaired renal function, and at a dose of 62.5 mcg (0.0625 mg) in patients with marked renal impairment. Doses may be increased every 2 weeks according to clinical response.
In a subset of approximately 1,800 patients enrolled in the DIG trial (wherein dosing was based on an algorithm similar to that in Table 5) the mean (± SD) serum digoxin concentrations at 1 month and 12 months were 1.01 ± 0.47 ng/mL and 0.97 ± 0.43 ng/mL, respectively. There are no rigid guidelines as to the range of serum concentrations that are most efficacious. Several post hoc analyses of heart failure patients in the DIG trial suggest that the optimal trough digoxin serum level may be 0.5 ng/mL to 1 ng/mL.
The maintenance dose should be based upon the percentage of the peak body stores lost each day through elimination. The following formula has had wide clinical use:
Maintenance Dose = Peak Body Stores (i.e., Loading Dose) x % Daily Loss/100
Where: % Daily Loss = 14 + Ccr/5
(Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area.)
Table 5 provides average daily maintenance dose requirements of LANOXIN Tablets for patients with heart failure based upon lean body weight and renal function:
Table 5. Usual Daily Maintenance Dose Requirements (mcg) of LANOXIN for Estimated Peak Body Stores of 10 mcg/kgCorrected Ccr
(mL/min per 70 kg)a
Lean Body Weight
Number of Days
kg
50
60
70
80
90
100
Before Steady
lb
110
132
154
176
198
220
State Achievedb
0
62.5c
125
125
125
187.5
187.5
22
10
125
125
125
187.5
187.5
187.5
19
20
125
125
187.5
187.5
187.5
250
16
30
125
187.5
187.5
187.5
250
250
14
40
125
187.5
187.5
250
250
250
13
50
187.5
187.5
250
250
250
250
12
60
187.5
187.5
250
250
250
375
11
70
187.5
250
250
250
250
375
10
80
187.5
250
250
250
375
375
9
90
187.5
250
250
250
375
500
8
100
250
250
250
375
375
500
7
aCcr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area. For adults, if only serum creatinine concentrations (Scr) are available, a Ccr (corrected to 70 kg body weight) may be estimated in men as (140 - Age)/Scr. For women, this result should be multiplied by 0.85. Note: This equation cannot be used for estimating creatinine clearance in infants or children.
bIf no loading dose administered.
c62.5 mcg = 0.0625 mg.
Example: Based on Table 5, a patient in heart failure with an estimated lean body weight of 70 kg and a Ccr of 60 mL/min should be given a dose of 250 mcg (0.25 mg) daily of LANOXIN Tablets, usually taken after the morning meal. If no loading dose is administered, steady-state serum concentrations in this patient should be anticipated at approximately 11 days.
Infants and ChildrenIn general, divided daily dosing is recommended for infants and young children (under age 10). In the newborn period, renal clearance of digoxin is diminished and suitable dosage adjustments must be observed. This is especially pronounced in the premature infant. Beyond the immediate newborn period, children generally require proportionally larger doses than adults on the basis of body weight or body surface area. Children over 10 years of age require adult dosages in proportion to their body weight. Some researchers have suggested that infants and young children tolerate slightly higher serum concentrations than do adults.
Daily maintenance doses for each age group are given in Table 6 and should provide therapeutic effects with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. These recommendations assume the presence of normal renal function:
Table 6. Daily Maintenance Doses in Children With Normal Renal FunctionAge
Daily Maintenance Dose (mcg/kg)
2 to 5 Years
10 to 15
5 to 10 Years
7 to 10
Over 10 Years
3 to 5
In children with renal disease, digoxin must be carefully titrated based upon clinical response.
It cannot be overemphasized that both the adult and pediatric dosage guidelines provided are based upon average patient response and substantial individual variation can be expected. Accordingly, ultimate dosage selection must be based upon clinical assessment of the patient.
Atrial Fibrillation: Peak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects. Data are not available to establish the appropriate resting or exercise target rates that should be achieved.
Dosage Adjustment When Changing PreparationsThe difference in bioavailability between LANOXIN Injection or LANOXIN Tablets must be considered when changing patients from one dosage form to the other.
-
Rx Pak Division Of Mckesson Corporation
Lanoxin | Rx Pak Division Of Mckesson Corporation
2.1 Important Dosing InformationIn selecting a LANOXIN dosing regimen, it is important to consider factors that affect digoxin blood levels (e.g., body weight, age, renal function, concomitant drugs) since toxic levels of digoxin are only slightly higher than therapeutic levels. Dosing can be either initiated with a loading dose followed by maintenance dosing if rapid titration is desired or initiated with maintenance dosing without a loading dose.
Consider interruption or reduction in digoxin dose prior to electrical cardioversion [see Warnings and Precautions (5.6)].
Use digoxin solution to obtain the appropriate dose in infants, young pediatric patients, or patients with very low body weight.
2.2 Loading Dosing Regimen in Adults and Pediatric PatientsFor adults and pediatric patients if a loading dosage is to be given, administer half the total loading dose initially, then ¼ the loading dose every 4 to 8 hours twice, with careful assessment of clinical response and toxicity before each dose. The recommended loading dose is displayed in Table 1.
Table 1. Recommended LANOXIN Oral Loading Dose mcg = microgramsAge
Oral Loading Dose, mcg/kg
5 to 10 years
20 - 45
Adults and pediatric patients over 10 years
10 - 15
2.3 Maintenance Dosing in Adults and Pediatric Patients Over 10 Years OldThe maintenance dose is based on the lean body weight, renal function, age, and concomitant products [see Drug Interactions (7.1, 7.2, 7.3)].
The recommended starting maintenance dosage in adults and pediatric patients over 10 years old is displayed in Table 2. Doses may be increased every 2 weeks according to clinical response, serum drug levels, and toxicity.
Table 2. Recommended Starting LANOXIN Maintenance Dosage in Adults and Pediatric Patients Over 10 Years Old mcg = microgramsAge
Oral Maintenance Dose, mcg/kg/day
(given once daily)Adults and pediatric patients over 10 years
3.4 – 5.1
Table 3 displays the recommended (once daily) maintenance dose of LANOXIN in pediatric patients over 10 years old and adult patients according to lean body weight and renal function. The doses are based on studies in adult patients with heart failure. Alternatively, the maintenance dose may be estimated by the following formula (peak body stores lost each day through elimination):
Total Maintenance Dose = Loading Dose (i.e., Peak Body Stores) x % Daily Loss/100
(% Daily Loss = 14 + Creatinine clearance/5)Reduce the dose of LANOXIN in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.
Table 3. Recommended Maintenance Dose (in micrograms given once daily) of LANOXIN in Pediatric Patients Over 10 Years Old and Adults by Lean Body Weight and by Renal Functiona a Doses are rounded to the nearest dose possible using whole and/or half LANOXIN tablets. Recommended doses approximately 30 percent lower than the calculated dose are designated with an *. Monitor digoxin levels in patients receiving these initial doses and increase dose if needed.
b For adults, creatinine clearance was corrected to 70-kg body weight or 1.73 m2 body surface area. If only serum creatinine concentrations (Scr) are available, a corrected Ccr may be estimated in men as (140 – Age)/Scr. For women, this result should be multiplied by 0.85.
For pediatric patients, the modified Schwartz equation may be used. The formula is based on height in cm and Scr in mg/dL where k is a constant. Ccr is corrected to 1.73 m2 body surface area. During the first year of life, the value of k is 0.33 for pre-term babies and 0.45 for term infants. The k is 0.55 for pediatric patients and adolescent girls and 0.7 for adolescent boys.
GFR (mL/min/1.73 m2) = (k x Height)/Scr
c If no loading dose administered.
d The doses listed assume average body composition.Corrected
Creatinine
ClearancebNumber of
Days Before
Steady State
AchievedcLean Body Weightd
kg
40
50
60
70
80
90
100
lb
88
110
132
154
176
198
220
10 mL/min
62.5*
125
125
187.5
187.5
187.5
250
19
20 mL/min
125
125
125
187.5
187.5
250
250
16
30 mL/min
125
125
187.5
187.5
250
250
312.5
14
40 mL/min
125
187.5
187.5
250
250
312.5
312.5
13
50 mL/min
125
187.5
187.5
250
250
312.5
312.5
12
60 mL/min
125
187.5
250
250
312.5
312.5
375
11
70 mL/min
187.5
187.5
250
250
312.5
375
375
10
80 mL/min
187.5
187.5
250
312.5
312.5
375
437.5
9
90 mL/min
187.5
250
250
312.5
375
437.5
437.5
8
100 mL/min
187.5
250
312.5
312.5
375
437.5
500
7
2.4 Maintenance Dosing in Pediatric Patients Less Than 10 Years OldThe starting maintenance dose for heart failure in pediatric patients less than 10 years old is based on the lean body weight, renal function, age, and concomitant products [see Drug Interactions (7.1, 7.2, 7.3)]. The recommended starting maintenance dose for pediatric patients between 5 and 10 years old with normal renal function is displayed in Table 4.
Table 4. Recommended Starting LANOXIN Maintenance Dosage in Pediatric Patients Between 5 and 10 Years OldAge
Daily Oral
Maintenance Dose,
mcg/kg/dayDose Regimen,
mcg/kg/dose5 to 10 years
6.4 – 12.9
3.2 – 6.4 Twice daily
The recommended maintenance dose (to be given twice daily) is presented in Table 5.
Table 5. Recommended Maintenance Dose (in micrograms given twice daily) of LANOXIN in Pediatric Patients <10 Years of Agea Based upon Lean Body Weight and Renal Functiona,b a Recommended are doses to be given twice daily.
b The doses are rounded to the nearest dose possible using whole and/or half LANOXIN tablets. Recommended doses approximately 30 percent lower than the calculated dose are designated with an *. Monitor digoxin levels in patients receiving these initial doses and increase dose if needed.
c The modified Schwartz equation may be used to estimate creatinine clearance. See footnote b under Table 2.
d If no loading dose administered.Corrected
Creatinine
ClearancecNumber of
Days Before
Steady State
AchieveddLean Body Weight
kg
20
30
40
50
60
lb
44
66
88
110
132
10 mL/min
-
62.5
62.5*
125
125
19
20 mL/min
62.5
62.5
125
125
125
16
30 mL/min
62.5
62.5*
125
125
187.5
14
40 mL/min
62.5
62.5*
125
187.5
187.5
13
50 mL/min
62.5
125
125
187.5
187.5
12
60 mL/min
62.5
125
125
187.5
250
11
70 mL/min
62.5
125
187.5
187.5
250
10
80 mL/min
62.5*
125
187.5
187.5
250
9
90 mL/min
62.5*
125
187.5
250
250
8
100 mL/min
62.5*
125
187.5
250
312.5
7
2.5 Monitoring to Assess Safety, Efficacy, and Therapeutic Blood LevelsMonitor for signs and symptoms of digoxin toxicity and clinical response. Adjust dose based on toxicity, efficacy, and blood levels.
Serum digoxin levels < 0.5 ng/mL have been associated with diminished efficacy, while levels above 2 ng/mL have been associated with increased toxicity without increased benefit.
Interpret the serum digoxin concentration in the overall clinical context, and do not use an isolated measurement of serum digoxin concentration as the basis for increasing or decreasing the LANOXIN dose. Serum digoxin concentrations may be falsely elevated by endogenous digoxin-like substances [see Drug Interactions (7.4)]. If the assay is sensitive to these substances, consider obtaining a baseline digoxin level before starting LANOXIN and correct post-treatment values by the reported baseline level.
Obtain serum digoxin concentrations just before the next scheduled LANOXIN dose or at least 6 hours after the last dose. The digoxin concentration is likely to be 10% to 25% lower when sampled right before the next dose (24 hours after dosing) compared to sampling 8 hours after dosing (using once-daily dosing). However, there will be only minor differences in digoxin concentrations using twice daily dosing whether sampling is done at 8 or 12 hours after a dose.
2.6 Switching from Intravenous Digoxin to Oral DigoxinWhen switching from intravenous to oral digoxin formulations, make allowances for differences in bioavailability when calculating maintenance dosages (see Table 6).
Table 6. Comparison of the Systemic Availability and Equivalent Doses of Oral and Intravenous LANOXINAbsolute
BioavailabilityEquivalent Doses (in micrograms)
LANOXIN Tablets
60 - 80%
62.5
125
250
500
LANOXIN Intravenous Injection
100%
50
100
200
400
-
Cardinal Health
Lanoxin | Cardinal Health
GeneralRecommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications. In selecting a dose of digoxin, the following factors must be considered:
1. The body weight of the patient. Doses should be calculated based upon lean (i.e., ideal) body weight. 2. The patient’s renal function, preferably evaluated on the basis of estimated creatinine clearance. 3. The patient’s age. Infants and children require different doses of digoxin than adults. Also, advanced age may be indicative of diminished renal function even in patients with normal serum creatinine concentration (i.e., below 1.5 mg/dL). 4. Concomitant disease states, concurrent medications, or other factors likely to alter the pharmacokinetic or pharmacodynamic profile of digoxin (see PRECAUTIONS). Serum Digoxin ConcentrationsIn general, the dose of digoxin used should be determined on clinical grounds. However, measurement of serum digoxin concentrations can be helpful to the clinician in determining the adequacy of digoxin therapy and in assigning certain probabilities to the likelihood of digoxin intoxication. About two-thirds of adults considered adequately digitalized (without evidence of toxicity) have serum digoxin concentrations ranging from 0.8 to 2.0 ng/mL (lower serum trough concentrations of 0.5 to 1 ng/mL may be appropriate in some adult patients, see Maintenance Dosing). However, digoxin may produce clinical benefits even at serum concentrations below this range. About two-thirds of adult patients with clinical toxicity have serum digoxin concentrations greater than 2.0 ng/mL. However, since one-third of patients with clinical toxicity have concentrations less than 2.0 ng/mL, values below 2.0 ng/mL do not rule out the possibility that a certain sign or symptom is related to digoxin therapy. Rarely, there are patients who are unable to tolerate digoxin at serum concentrations below 0.8 ng/mL. Consequently, the serum concentration of digoxin should always be interpreted in the overall clinical context, and an isolated measurement should not be used alone as the basis for increasing or decreasing the dose of the drug.
To allow adequate time for equilibration of digoxin between serum and tissue, sampling of serum concentrations should be done just before the next scheduled dose of the drug. If this is not possible, sampling should be done at least 6 to 8 hours after the last dose, regardless of the route of administration or the formulation used. On a once-daily dosing schedule, the concentration of digoxin will be 10% to 25% lower when sampled at 24 versus 8 hours, depending upon the patient’s renal function. On a twice-daily dosing schedule, there will be only minor differences in serum digoxin concentrations whether sampling is done at 8 or 12 hours after a dose.
If a discrepancy exists between the reported serum concentration and the observed clinical response, the clinician should consider the following possibilities:
1. Analytical problems in the assay procedure. 2. Inappropriate serum sampling time. 3. Administration of a digitalis glycoside other than digoxin. 4. Conditions (described in WARNINGS and PRECAUTIONS) causing an alteration in the sensitivity of the patient to digoxin. 5. Serum digoxin concentration may decrease acutely during periods of exercise without any associated change in clinical efficacy due to increased binding of digoxin to skeletal muscle. Heart Failure AdultsDigitalization may be accomplished by either of 2 general approaches that vary in dosage and frequency of administration, but reach the same endpoint in terms of total amount of digoxin accumulated in the body.
1. If rapid digitalization is considered medically appropriate, it may be achieved by administering a loading dose based upon projected peak digoxin body stores. Maintenance dose can be calculated as a percentage of the loading dose. 2. More gradual digitalization may be obtained by beginning an appropriate maintenance dose, thus allowing digoxin body stores to accumulate slowly. Steady-state serum digoxin concentrations will be achieved in approximately 5 half-lives of the drug for the individual patient. Depending upon the patient’s renal function, this will take between 1 and 3 weeks. Rapid Digitalization With a Loading DosePeak digoxin body stores of 8 to 12 mcg/kg should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. Because of altered digoxin distribution and elimination, projected peak body stores for patients with renal insufficiency should be conservative (i.e., 6 to 10 mcg/kg) (see PRECAUTIONS).
The loading dose should be administered in several portions, with roughly half the total given as the first dose. Additional fractions of this planned total dose may be given at 6- to 8-hour intervals, with careful assessment of clinical response before each additional dose.
If the patient’s clinical response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.
A single initial dose of 500 to 750 mcg (0.5 to 0.75 mg) of LANOXIN Tablets usually produces a detectable effect in 0.5 to 2 hours that becomes maximal in 2 to 6 hours. Additional doses of 125 to 375 mcg (0.125 to 0.375 mg) may be given cautiously at 6- to 8-hour intervals until clinical evidence of an adequate effect is noted. The usual amount of LANOXIN Tablets that a 70-kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 750 to 1,250 mcg (0.75 to 1.25 mg).
LANOXIN Injection is frequently used to achieve rapid digitalization, with conversion to LANOXIN Tablets for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see Table 1, CLINICAL PHARMACOLOGY).
Maintenance DosingThe doses of digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg (0.125 to 0.5 mg) once daily. In these studies, the digoxin dose has been generally titrated according to the patient’s age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg (0.25 mg) once daily in patients under age 70 with good renal function, at a dose of 125 mcg (0.125 mg) once daily in patients over age 70 or with impaired renal function, and at a dose of 62.5 mcg (0.0625 mg) in patients with marked renal impairment. Doses may be increased every 2 weeks according to clinical response.
In a subset of approximately 1,800 patients enrolled in the DIG trial (wherein dosing was based on an algorithm similar to that in Table 5) the mean (± SD) serum digoxin concentrations at 1 month and 12 months were 1.01 ± 0.47 ng/mL and 0.97 ± 0.43 ng/mL, respectively. There are no rigid guidelines as to the range of serum concentrations that are most efficacious. Several post hoc analyses of heart failure patients in the DIG trial suggest that the optimal trough digoxin serum level may be 0.5 ng/mL to 1 ng/mL.
The maintenance dose should be based upon the percentage of the peak body stores lost each day through elimination. The following formula has had wide clinical use:
Maintenance Dose = Peak Body Stores (i.e., Loading Dose) x % Daily Loss/100
Where: % Daily Loss = 14 + Ccr/5
(Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area.)
Table 5 provides average daily maintenance dose requirements of LANOXIN Tablets for patients with heart failure based upon lean body weight and renal function:
Table 5. Usual Daily Maintenance Dose Requirements (mcg) of LANOXIN for Estimated Peak Body Stores of 10 mcg/kgCorrected Ccr
(mL/min per 70 kg)a
Lean Body Weight
Number of Days
kg
50
60
70
80
90
100
Before Steady
lb
110
132
154
176
198
220
State Achievedb
0
62.5c
125
125
125
187.5
187.5
22
10
125
125
125
187.5
187.5
187.5
19
20
125
125
187.5
187.5
187.5
250
16
30
125
187.5
187.5
187.5
250
250
14
40
125
187.5
187.5
250
250
250
13
50
187.5
187.5
250
250
250
250
12
60
187.5
187.5
250
250
250
375
11
70
187.5
250
250
250
250
375
10
80
187.5
250
250
250
375
375
9
90
187.5
250
250
250
375
500
8
100
250
250
250
375
375
500
7
aCcr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area. For adults, if only serum creatinine concentrations (Scr) are available, a Ccr (corrected to 70 kg body weight) may be estimated in men as (140 - Age)/Scr. For women, this result should be multiplied by 0.85. Note: This equation cannot be used for estimating creatinine clearance in infants or children.
bIf no loading dose administered.
c62.5 mcg = 0.0625 mg.
Example: Based on Table 5, a patient in heart failure with an estimated lean body weight of 70 kg and a Ccr of 60 mL/min should be given a dose of 250 mcg (0.25 mg) daily of LANOXIN Tablets, usually taken after the morning meal. If no loading dose is administered, steady-state serum concentrations in this patient should be anticipated at approximately 11 days.
Infants and ChildrenIn general, divided daily dosing is recommended for infants and young children (under age 10). In the newborn period, renal clearance of digoxin is diminished and suitable dosage adjustments must be observed. This is especially pronounced in the premature infant. Beyond the immediate newborn period, children generally require proportionally larger doses than adults on the basis of body weight or body surface area. Children over 10 years of age require adult dosages in proportion to their body weight. Some researchers have suggested that infants and young children tolerate slightly higher serum concentrations than do adults.
Daily maintenance doses for each age group are given in Table 6 and should provide therapeutic effects with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. These recommendations assume the presence of normal renal function:
Table 6. Daily Maintenance Doses in Children With Normal Renal FunctionAge
Daily Maintenance Dose (mcg/kg)
2 to 5 Years
10 to 15
5 to 10 Years
7 to 10
Over 10 Years
3 to 5
In children with renal disease, digoxin must be carefully titrated based upon clinical response.
It cannot be overemphasized that both the adult and pediatric dosage guidelines provided are based upon average patient response and substantial individual variation can be expected. Accordingly, ultimate dosage selection must be based upon clinical assessment of the patient.
Atrial Fibrillation: Peak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects. Data are not available to establish the appropriate resting or exercise target rates that should be achieved.
Dosage Adjustment When Changing PreparationsThe difference in bioavailability between LANOXIN Injection or LANOXIN Tablets must be considered when changing patients from one dosage form to the other.
-
Aphena Pharma Solutions – Tennessee, Llc
Lanoxin | Aphena Pharma Solutions - Tennessee, Llc
GeneralRecommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications. In selecting a dose of digoxin, the following factors must be considered:
1. The body weight of the patient. Doses should be calculated based upon lean (i.e., ideal) body weight. 2. The patient’s renal function, preferably evaluated on the basis of estimated creatinine clearance. 3. The patient’s age. Infants and children require different doses of digoxin than adults. Also, advanced age may be indicative of diminished renal function even in patients with normal serum creatinine concentration (i.e., below 1.5 mg/dL). 4. Concomitant disease states, concurrent medications, or other factors likely to alter the pharmacokinetic or pharmacodynamic profile of digoxin (see PRECAUTIONS). Serum Digoxin ConcentrationsIn general, the dose of digoxin used should be determined on clinical grounds. However, measurement of serum digoxin concentrations can be helpful to the clinician in determining the adequacy of digoxin therapy and in assigning certain probabilities to the likelihood of digoxin intoxication. About two-thirds of adults considered adequately digitalized (without evidence of toxicity) have serum digoxin concentrations ranging from 0.8 to 2.0 ng/mL (lower serum trough concentrations of 0.5 to 1 ng/mL may be appropriate in some adult patients, see Maintenance Dosing). However, digoxin may produce clinical benefits even at serum concentrations below this range. About two-thirds of adult patients with clinical toxicity have serum digoxin concentrations greater than 2.0 ng/mL. However, since one-third of patients with clinical toxicity have concentrations less than 2.0 ng/mL, values below 2.0 ng/mL do not rule out the possibility that a certain sign or symptom is related to digoxin therapy. Rarely, there are patients who are unable to tolerate digoxin at serum concentrations below 0.8 ng/mL. Consequently, the serum concentration of digoxin should always be interpreted in the overall clinical context, and an isolated measurement should not be used alone as the basis for increasing or decreasing the dose of the drug.
To allow adequate time for equilibration of digoxin between serum and tissue, sampling of serum concentrations should be done just before the next scheduled dose of the drug. If this is not possible, sampling should be done at least 6 to 8 hours after the last dose, regardless of the route of administration or the formulation used. On a once-daily dosing schedule, the concentration of digoxin will be 10% to 25% lower when sampled at 24 versus 8 hours, depending upon the patient’s renal function. On a twice-daily dosing schedule, there will be only minor differences in serum digoxin concentrations whether sampling is done at 8 or 12 hours after a dose.
If a discrepancy exists between the reported serum concentration and the observed clinical response, the clinician should consider the following possibilities:
1. Analytical problems in the assay procedure. 2. Inappropriate serum sampling time. 3. Administration of a digitalis glycoside other than digoxin. 4. Conditions (described in WARNINGS and PRECAUTIONS) causing an alteration in the sensitivity of the patient to digoxin. 5. Serum digoxin concentration may decrease acutely during periods of exercise without any associated change in clinical efficacy due to increased binding of digoxin to skeletal muscle. Heart Failure AdultsDigitalization may be accomplished by either of 2 general approaches that vary in dosage and frequency of administration, but reach the same endpoint in terms of total amount of digoxin accumulated in the body.
1. If rapid digitalization is considered medically appropriate, it may be achieved by administering a loading dose based upon projected peak digoxin body stores. Maintenance dose can be calculated as a percentage of the loading dose. 2. More gradual digitalization may be obtained by beginning an appropriate maintenance dose, thus allowing digoxin body stores to accumulate slowly. Steady-state serum digoxin concentrations will be achieved in approximately 5 half-lives of the drug for the individual patient. Depending upon the patient’s renal function, this will take between 1 and 3 weeks. Rapid Digitalization With a Loading DosePeak digoxin body stores of 8 to 12 mcg/kg should provide therapeutic effect with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. Because of altered digoxin distribution and elimination, projected peak body stores for patients with renal insufficiency should be conservative (i.e., 6 to 10 mcg/kg) (see PRECAUTIONS).
The loading dose should be administered in several portions, with roughly half the total given as the first dose. Additional fractions of this planned total dose may be given at 6- to 8-hour intervals, with careful assessment of clinical response before each additional dose.
If the patient’s clinical response necessitates a change from the calculated loading dose of digoxin, then calculation of the maintenance dose should be based upon the amount actually given.
A single initial dose of 500 to 750 mcg (0.5 to 0.75 mg) of LANOXIN Tablets usually produces a detectable effect in 0.5 to 2 hours that becomes maximal in 2 to 6 hours. Additional doses of 125 to 375 mcg (0.125 to 0.375 mg) may be given cautiously at 6- to 8-hour intervals until clinical evidence of an adequate effect is noted. The usual amount of LANOXIN Tablets that a 70-kg patient requires to achieve 8 to 12 mcg/kg peak body stores is 750 to 1,250 mcg (0.75 to 1.25 mg).
LANOXIN Injection is frequently used to achieve rapid digitalization, with conversion to LANOXIN Tablets for maintenance therapy. If patients are switched from intravenous to oral digoxin formulations, allowances must be made for differences in bioavailability when calculating maintenance dosages (see Table 1, CLINICAL PHARMACOLOGY).
Maintenance DosingThe doses of digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg (0.125 to 0.5 mg) once daily. In these studies, the digoxin dose has been generally titrated according to the patient’s age, lean body weight, and renal function. Therapy is generally initiated at a dose of 250 mcg (0.25 mg) once daily in patients under age 70 with good renal function, at a dose of 125 mcg (0.125 mg) once daily in patients over age 70 or with impaired renal function, and at a dose of 62.5 mcg (0.0625 mg) in patients with marked renal impairment. Doses may be increased every 2 weeks according to clinical response.
In a subset of approximately 1,800 patients enrolled in the DIG trial (wherein dosing was based on an algorithm similar to that in Table 5) the mean (± SD) serum digoxin concentrations at 1 month and 12 months were 1.01 ± 0.47 ng/mL and 0.97 ± 0.43 ng/mL, respectively. There are no rigid guidelines as to the range of serum concentrations that are most efficacious. Several post hoc analyses of heart failure patients in the DIG trial suggest that the optimal trough digoxin serum level may be 0.5 ng/mL to 1 ng/mL.
The maintenance dose should be based upon the percentage of the peak body stores lost each day through elimination. The following formula has had wide clinical use:
Maintenance Dose = Peak Body Stores (i.e., Loading Dose) x % Daily Loss/100
Where: % Daily Loss = 14 + Ccr/5
(Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area.)
Table 5 provides average daily maintenance dose requirements of LANOXIN Tablets for patients with heart failure based upon lean body weight and renal function:
Table 5. Usual Daily Maintenance Dose Requirements (mcg) of LANOXIN for Estimated Peak Body Stores of 10 mcg/kgCorrected Ccr
(mL/min per 70 kg)a
Lean Body Weight
Number of Days
kg
50
60
70
80
90
100
Before Steady
lb
110
132
154
176
198
220
State Achievedb
0
62.5c
125
125
125
187.5
187.5
22
10
125
125
125
187.5
187.5
187.5
19
20
125
125
187.5
187.5
187.5
250
16
30
125
187.5
187.5
187.5
250
250
14
40
125
187.5
187.5
250
250
250
13
50
187.5
187.5
250
250
250
250
12
60
187.5
187.5
250
250
250
375
11
70
187.5
250
250
250
250
375
10
80
187.5
250
250
250
375
375
9
90
187.5
250
250
250
375
500
8
100
250
250
250
375
375
500
7
a Ccr is creatinine clearance, corrected to 70 kg body weight or 1.73 m2 body surface area. For adults, if only serum creatinine concentrations (Scr) are available, a Ccr (corrected to 70 kg body weight) may be estimated in men as (140 - Age)/Scr. For women, this result should be multiplied by 0.85. Note: This equation cannot be used for estimating creatinine clearance in infants or children.
b If no loading dose administered.
c 62.5 mcg = 0.0625 mg.
Example: Based on Table 5, a patient in heart failure with an estimated lean body weight of 70 kg and a Ccr of 60 mL/min should be given a dose of 250 mcg (0.25 mg) daily of LANOXIN Tablets, usually taken after the morning meal. If no loading dose is administered, steady-state serum concentrations in this patient should be anticipated at approximately 11 days.
Infants and ChildrenIn general, divided daily dosing is recommended for infants and young children (under age 10). In the newborn period, renal clearance of digoxin is diminished and suitable dosage adjustments must be observed. This is especially pronounced in the premature infant. Beyond the immediate newborn period, children generally require proportionally larger doses than adults on the basis of body weight or body surface area. Children over 10 years of age require adult dosages in proportion to their body weight. Some researchers have suggested that infants and young children tolerate slightly higher serum concentrations than do adults.
Daily maintenance doses for each age group are given in Table 6 and should provide therapeutic effects with minimum risk of toxicity in most patients with heart failure and normal sinus rhythm. These recommendations assume the presence of normal renal function:
Table 6. Daily Maintenance Doses in Children With Normal Renal FunctionAge
Daily Maintenance Dose (mcg/kg)
2 to 5 Years
10 to 15
5 to 10 Years
7 to 10
Over 10 Years
3 to 5
In children with renal disease, digoxin must be carefully titrated based upon clinical response.
It cannot be overemphasized that both the adult and pediatric dosage guidelines provided are based upon average patient response and substantial individual variation can be expected. Accordingly, ultimate dosage selection must be based upon clinical assessment of the patient.
Atrial FibrillationPeak digoxin body stores larger than the 8 to 12 mcg/kg required for most patients with heart failure and normal sinus rhythm have been used for control of ventricular rate in patients with atrial fibrillation. Doses of digoxin used for the treatment of chronic atrial fibrillation should be titrated to the minimum dose that achieves the desired ventricular rate control without causing undesirable side effects. Data are not available to establish the appropriate resting or exercise target rates that should be achieved.
Dosage Adjustment When Changing PreparationsThe difference in bioavailability between LANOXIN Injection or LANOXIN Tablets must be considered when changing patients from one dosage form to the other.
-
Cardinal Health
Lanoxin | Sasa Cosmetics
DIRECTIONS: Apply liberally 15 minutes before sun exposure --
reapply. After 80 minutes of swimming or sweating, immediately after towel
drying and at least every 2 hours -- Sun Protection Measures-Spending time in the
sun increases your risk of skin cancer and early skin aging. To
decrease this risk, regularly use a sunscreen with a broad spectrum SPF of
15 or higher and other sun protection measures including: - Limit time
in the sun, especially from 10 a.m. to 2 p.m. -- Wear long-sleeve shirts, pants,
hats, and sunglasses -- Children under 6 months: Ask a doctor.
-
Cardinal Health
Lanoxin | Dolgencorp, Llc
do not take more than directed (see overdose warning) adults and children 12 years and over: take 2 caplets every 4 hours swallow whole - do not crush, chew, or dissolve do not take more than 10 caplets in 24 hours children under 12 years: ask a doctor -
Covis Pharmaceuticals, Inc.
Lanoxin | Baxter Healthcare Corporation
All injections in VIAFLEX plastic containers are intended for intravenous administration using sterile and nonpyrogenic equipment.
As directed by a physician. Dosage, rate, and duration of administration are to be individualized and dependent upon the indication for use, the patient’s age, weight, concomitant treatment and clinical condition of the patient as well as laboratory determinations.
The dosage and constant infusion rate of intravenous dextrose must be selected with caution in pediatric patients, particularly neonates and low weight infants, because of the increased risk of hyperglycemia/hypoglycemia. Frequent monitoring of serum glucose concentrations is required when dextrose is prescribed to pediatric patients, particularly neonates and low birth weight infants. The infusion rate and volume depends on the age, weight, clinical and metabolic conditions of the patient, concomitant therapy and should be determined by the consulting physician experienced in pediatric intravenous fluid therapy.
After opening the container, the contents should be used immediately and should not be stored for a subsequent infusion. Do not reconnect any partially used containers.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. Use of a final filter is recommended during administration of all parenteral solutions, where possible.
Do not administer unless the solution is clear and the seal is intact.
Additives may be incompatible with PLASMA-LYTE 56 and 5% Dextrose Injection (Multiple Electrolytes and Dextrose Injection, Type 1, USP). As with all parenteral solutions, compatibility of the additives with the solution must be assessed before addition. Before adding a substance or medication, verify that it is soluble and/or stable in water and that the pH range of PLASMA-LYTE 56 and 5% Dextrose Injection (Multiple Electrolytes and Dextrose Injection, Type 1, USP) is appropriate. After addition, check for possible color change and/or the appearance of precipitates, insoluble complexes or crystals.
The instructions for use of the medication to be added and other relevant literature must be consulted. Additives known or determined to be incompatible must not be used. When introducing additives to PLASMA-LYTE 56 and 5% Dextrose Injection (Multiple Electrolytes and Dextrose Injection, Type 1, USP), aseptic technique must be used. Mix the solution thoroughly when additives have been introduced. Do not store solutions containing additives.
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Concordia Pharmaceuticals Inc.
Lanoxin | Concordia Pharmaceuticals Inc.
2.1 Important Dosing and Administration InformationIn selecting a LANOXIN dosing regimen, it is important to consider factors that affect digoxin blood levels (e.g., body weight, age, renal function, concomitant drugs) since toxic levels of digoxin are only slightly higher than therapeutic levels. Dosing can be either initiated with a loading dose followed by maintenance dosing if rapid titration is desired or initiated with maintenance dosing without a loading dose.
Consider interruption or reduction in LANOXIN dose prior to electrical cardioversion [see Warnings and Precautions (5.4)].
Use digoxin solution to obtain the appropriate dose in infants, young pediatric patients, or patients with very low body weight.
2.2 Loading Dosing Regimen in Adults and Pediatric PatientsFor adults and pediatric patients if a loading dosage is to be given, administer half the total loading dose initially, then ¼ the loading dose every 6-8 hours twice, with careful assessment of clinical response and toxicity before each dose. The recommended loading dose is displayed in Table 1.
Table 1. Recommended LANOXIN Oral Loading Dose mcg = microgramAge
Total Oral Loading Dose (mcg/kg)
Administer half the total loading dose initially,
then ¼ the loading dose every 6 to 8 hours twice5 to 10 years
20-45
Adults and pediatric patients over 10 years
10-15
2.3 Maintenance Dosing in Adults and Pediatric Patients Over 10 Years OldThe maintenance dose is based on lean body weight, renal function, age, and concomitant products [see Clinical Pharmacology (12.3)].
The recommended starting maintenance dose in adults and pediatric patients over 10 years old with normal renal function is given in Table 2. Doses may be increased every 2 weeks according to clinical response, serum drug levels, and toxicity.
Table 2. Recommended Starting LANOXIN Maintenance Dosage in Adults and Pediatric Patients Over 10 Years Old mcg = microgramAge
Total Oral Maintenance Dose, mcg/kg/day
(given once daily)Adults and pediatric patients over 10 years
3.4-5.1
Table 3 provides the recommended (once daily) maintenance dose for adults and pediatric patients over 10 years old (to be given once daily) according to lean body weight and renal function. The doses are based on studies in adult patients with heart failure. Alternatively, the maintenance dose may be estimated by the following formula (peak body stores lost each day through elimination):
Total Maintenance Dose = Loading Dose (i.e., Peak Body Stores) x % Daily Loss/100
(% Daily Loss = 14 + Creatinine clearance/5)Reduce the dose of LANOXIN in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.
Table 3. Recommended Maintenance Dose (in micrograms given once daily) of LANOXIN in Pediatric Patients Over 10 Years Old and Adults by Lean Body Weight and by Renal Functiona a Doses are rounded to the nearest dose possible using whole LANOXIN tablets. Recommended doses approximately 30 percent lower than the calculated dose are designated with an *. Monitor digoxin levels in patients receiving these initial doses and increase dose if needed.
bFor adults, creatinine clearance was corrected to 70-kg body weight or 1.73 m2 body surface area. If only serum creatinine concentrations (Scr) are available, a corrected Ccr may be estimated in men as (140 – Age)/Scr. For women, this result should be multiplied by 0.85.
For pediatric patients, the modified Schwartz equation may be used. The formula is based on height in cm and Scr in mg/dL where k is a constant. Ccr is corrected to 1.73 m2 body surface area. During the first year of life, the value of k is 0.33 for pre-term babies and 0.45 for term infants. The k is 0.55 for pediatric patients and adolescent girls and 0.7 for adolescent boys.
GFR (mL/min/1.73 m2) = (k x Height)/Scr
c If no loading dose administered.
d The doses listed assume average body composition.Corrected
Creatinine
ClearancebLean Body Weightd
Number of Days
Before Steady
State Achievedckg
40
50
60
70
80
90
100
10 mL/min
62.5*
125
125
187.5
187.5
187.5
250
19
20 mL/min
125
125
125
187.5
187.5
250
250
16
30 mL/min
125
125
187.5
187.5
250
250
312.5
14
40 mL/min
125
187.5
187.5
250
250
312.5
312.5
13
50 mL/min
125
187.5
187.5
250
250
312.5
312.5
12
60 mL/min
125
187.5
250
250
312.5
312.5
375
11
70 mL/min
187.5
187.5
250
250
312.5
375
375
10
80 mL/min
187.5
187.5
250
312.5
312.5
375
437.5
9
90 mL/min
187.5
250
250
312.5
375
437.5
437.5
8
100 mL/min
187.5
250
312.5
312.5
375
437.5
500
7
2.4 Maintenance Dosing in Pediatric Patients Less Than 10 Years OldThe starting maintenance dose for heart failure in pediatric patients less than 10 years old is based on lean body weight, renal function, age, and concomitant products [see Clinical Pharmacology (12.3)]. The recommended starting maintenance dose for pediatric patients between 5 years and 10 years old is given in Table 4. These recommendations assume the presence of normal renal function.
Table 4. Recommended Starting LANOXIN Oral Maintenance Dosage in Pediatric Patients between 5 and 10 Years OldAge
Oral Maintenance Dose,
mcg/kg/dose5 years to 10 years
3.2-6.4 Twice daily
Table 5 provides average daily maintenance dose requirements for pediatric patients between 5 and 10 years old (to be given twice daily) with heart failure based on age, lean body weight, and renal function.
Table 5. Recommended Maintenance Dose (in micrograms given TWICE daily) of LANOXIN in Pediatric Patients between 5 and 10 Years of Agea Based upon Lean Body Weight and Renal Functiona,b a Recommended are doses to be given twice daily.
b The doses are rounded to the nearest dose possible using whole LANOXIN tablets. Recommended doses approximately 30 percent lower than the calculated dose are designated with an *. Monitor digoxin levels in patients receiving these initial doses and increase dose if needed.
c The modified Schwartz equation may be used to estimate creatinine clearance. See footnote b under Table 3.
d If no loading dose administered.Corrected
Creatinine
ClearancecLean Body Weight
Number of Days
Before Steady
State Achieveddkg
20
30
40
50
60
10 mL/min
-
62.5
62.5*
125
125
19
20 mL/min
62.5
62.5
125
125
125
16
30 mL/min
62.5
62.5*
125
125
187.5
14
40 mL/min
62.5
62.5*
125
187.5
187.5
13
50 mL/min
62.5
125
125
187.5
187.5
12
60 mL/min
62.5
125
125
187.5
250
11
70 mL/min
62.5
125
187.5
187.5
250
10
80 mL/min
62.5*
125
187.5
187.5
250
9
90 mL/min
62.5*
125
187.5
250
250
8
100 mL/min
62.5*
125
187.5
250
312.5
7
2.5 Monitoring to Assess Safety, Efficacy, and Therapeutic Blood LevelsMonitor for signs and symptoms of digoxin toxicity and clinical response. Adjust dose based on toxicity, efficacy, and blood levels.
Serum digoxin levels less than 0.5 ng/mL have been associated with diminished efficacy, while levels above 2 ng/mL have been associated with increased toxicity without increased benefit.
Interpret the serum digoxin concentration in the overall clinical context, and do not use an isolated measurement of serum digoxin concentration as the basis for increasing or decreasing the LANOXIN dose. Serum digoxin concentrations may be falsely elevated by endogenous digoxin-like substances [see Drug Interactions (7.4)]. If the assay is sensitive to these substances, consider obtaining a baseline digoxin level before starting LANOXIN and correct post-treatment values by the reported baseline level.
Obtain serum digoxin concentrations just before the next scheduled LANOXIN dose or at least 6 hours after the last dose. The digoxin concentration is likely to be 10-25% lower when sampled right before the next dose (24 hours after dosing) compared to sampling 8 hours after dosing (using once-daily dosing). However, there will be only minor differences in digoxin concentrations using twice daily dosing whether sampling is done at 8 or 12 hours after a dose.
2.6 Switching from Intravenous Digoxin to Oral DigoxinWhen switching from intravenous to oral digoxin formulations, make allowances for differences in bioavailability when calculating maintenance dosages (see Table 6).
Table 6. Comparison of the Systemic Availability and Equivalent Doses of Oral and Intravenous LANOXINAbsolute
BioavailabilityEquivalent Doses (mcg)
LANOXIN Tablets
60-80%
62.5
125
250
500
LANOXIN Intravenous Injection
100%
50
100
200
400
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