Amplification of the vasodilatory effects of Isordil by sildenafil can result in severe hypotension. The time course and dose dependence of this interaction have not been studied. Appropriate supportive care has not been studied, but it seems reasonable to treat this as a nitrate overdose, with elevation of the the extremities and with central volume expansion.
The benefits of immediate-release oral isosorbide dinitrate in patients with acute myocardial infarction or congestive heart failure have not been established. If one elects to use isosorbide dinitrate in these conditions, careful clinical or hemodynamic monitoring must be used to avoid the hazards of hypotension and tachycardia. Because the effects of oral isosorbide dinitrate are so difficult to terminate rapidly, this formulation is not recommended in these settings.
Isordil (isosorbide dinitrate) Titradose tablets are indicated for the prevention of angina pectoris due to coronary artery disease. The onset of action of immediate-release oral isosorbide dinitrate is not sufficiently rapid for this product to be useful in aborting an acute anginal episode.
Isosorbide dinitrate (ISDN) is 1,4:3,6-dianhydro-D-glucitol 2,5-dinitrate, an organic nitrate whose structural formula is
and whose molecular weight is 236.14. The organic nitrates are vasodilators, active on both arteries and veins.
Isosorbide dinitrate is a white, crystalline, odorless compound which is stable in air and in solution, has a melting point of 70°C and has an optical rotation of +134° (c=1.0, alcohol, 20°C). Isosorbide dinitrate is freely soluble in organic solvents such as acetone, alcohol, and ether, but is only sparingly soluble in water.
Each Isordil® Titradose™ tablet contains 5 or 40 mg of isosorbide dinitrate. The inactive ingredients in each tablet are lactose, cellulose, and magnesium stearate. The 5 mg and 40 mg dosage strengths also contain the following: 5 mg – FD&C Red 40; 40 mg – D&C Yellow 10, FD&C Blue 1, and FD&C Yellow 6.
As noted under "CLINICAL PHARMACOLOGY," multiple-dose studies with ISDN and other nitrates have shown that maintenance of continuous 24-hour plasma levels results in refractory tolerance. Every dosing regimen for Isordil Titradose tablets must provide a daily dose-free interval to minimize the development of this tolerance. With immediate-release ISDN, it appears that one daily dose-free interval must be at least 14 hours long.
As also noted under "CLINICAL PHARMACOLOGY," the effects of the second and later doses have been smaller and shorter-lasting than the effects of the first.
Large controlled studies with other nitrates suggest that no dosing regimen with Isordil Titradose tablets should be expected to provide more than about 12 hours of continuous anti-anginal efficacy per day.
As with all titratable drugs, it is important to administer the minimum dose which produces the desired clinical effect. The usual starting dose of Isordil Titradose is 5 mg to 20 mg, two or three times daily. For maintenance therapy, 10 mg to 40 mg, two or three times daily is recommended. Some patients may require higher doses. A daily dose-free interval of at least 14 hours is advisable to minimize tolerance. The optimal interval will vary with the individual patient, dose and regimen.
Adults and children 12 years and over apply to affected area; change patch 1 to 2 times daily.
Children under 12 years, consult physician before use.
How to apply:
Clean and dry affected area
Cut open pouch and remove patch
Remove protective film and apply directly to the area of pain
Apply to affected area not more than 3 times daily
Wash hands with soap after applying patch
Reseal pouch containing unsed patches
As noted under "CLINICAL PHARMACOLOGY," multiple-dose studies with ISDN and other nitrates have shown that maintenance of continuous 24-hour plasma levels results in refractory tolerance. Every dosing regimen for Isordil Titradose tablets must provide a daily dose-free interval to minimize the development of this tolerance. With immediate-release ISDN, it appears that one daily dose-free interval must be at least 14 hours long.
As also noted under "CLINICAL PHARMACOLOGY," the effects of the second and later doses have been smaller and shorter-lasting than the effects of the first.
Large controlled studies with other nitrates suggest that no dosing regimen with Isordil Titradose tablets should be expected to provide more than about 12 hours of continuous anti-anginal efficacy per day.
As with all titratable drugs, it is important to administer the minimum dose which produces the desired clinical effect. The usual starting dose of Isordil Titradose is 5 mg to 20 mg, two or three times daily. For maintenance therapy, 10 mg to 40 mg, two or three times daily is recommended. Some patients may require higher doses. A daily dose-free interval of at least 14 hours is advisable to minimize tolerance. The optimal interval will vary with the individual patient, dose and regimen.