Hypertension
Dosing must be individualized. The usual starting dose of losartan is 50 mg once daily, with 25 mg recommended for patients with intravascular volume depletion (e.g., patients treated with diuretics) (see WARNINGS, Hypotension — Volume-Depleted Patients) and patients with a history of hepatic impairment (see WARNINGS, Impaired Hepatic Function). Losartan can be administered once or twice daily at total daily doses of 25 to 100 mg. If the antihypertensive effect measured at trough using once-a-day dosing is inadequate, a twice-a-day regimen at the same total daily dose or an increase in dose may give a more satisfactory response.
Hydrochlorothiazide is effective in doses of 12.5 to 50 mg once daily and can be given at doses of 12.5 to 25 mg as losartan potassium and hydrochlorothiazide tablets.
To minimize dose-independent side effects, it is usually appropriate to begin combination therapy only after a patient has failed to achieve the desired effect with monotherapy.
The side effects (see WARNINGS) of losartan are generally rare and apparently independent of dose; those of hydrochlorothiazide are a mixture of dose-dependent (primarily hypokalemia) and dose-independent phenomena (e.g., pancreatitis), the former much more common than the latter. Therapy with any combination of losartan and hydrochlorothiazide will be associated with both sets of dose-independent side effects.
Replacement Therapy
The combination may be substituted for the titrated components.
Dose Titration by Clinical Effect
A patient whose blood pressure is not adequately controlled with losartan monotherapy (see above) or hydrochlorothiazide alone may be switched to losartan potassium and hydrochlorothiazide tablets, USP 50 mg/12.5 mg once daily. If blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide tablets, USP 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide tablets, USP 100 mg/25 mg once daily. A patient whose blood pressure is not adequately controlled with losartan 100 mg monotherapy (see above) may be switched to losartan potassium and hydrochlorothiazide tablets, USP 100 mg/12.5 mg once daily. If blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide tablets, USP 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide tablets, USP 100 mg/25 mg once daily.
A patient whose blood pressure is inadequately controlled by 25 mg once daily of hydrochlorothiazide, or is controlled but who experiences hypokalemia with this regimen, may be switched to losartan potassium and hydrochlorothiazide tablets, USP 50 mg/12.5 mg once daily, reducing the dose of hydrochlorothiazide without reducing the overall expected antihypertensive response. The clinical response to losartan potassium and hydrochlorothiazide tablets, USP 50 mg/12.5 mg should be subsequently evaluated, and if blood pressure remains uncontrolled after about 3 weeks of therapy, the dose may be increased to two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily.
The usual dose of losartan potassium and hydrochlorothiazide is one tablet of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily. More than two tablets of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily or more than one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily is not recommended. The maximal antihypertensive effect is attained about 3 weeks after initiation of therapy.
Use in Patients with Renal Impairment
The usual regimens of therapy with losartan potassium and hydrochlorothiazide tablets may be followed as long as the patient's creatinine clearance is greater than 30 mL/min. In patients with more severe renal impairment, loop diuretics are preferred to thiazides, so losartan potassium and hydrochlorothiazide tablets are not recommended.
Patients with Hepatic Impairment
Losartan potassium and hydrochlorothiazide tablets are not recommended for titration in patients with hepatic impairment (see WARNINGS, Impaired Hepatic Function) because the appropriate 25 mg starting dose of losartan cannot be given.
Severe Hypertension
The starting dose of losartan potassium and hydrochlorothiazide tablets for initial treatment of severe hypertension is one tablet of losartan potassium and hydrochlorothiazide 50 mg/12.5 mg once daily (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects). For patients who do not respond adequately to losartan potassium and hydrochlorothiazide tablets, USP 50 mg/12.5 mg after 2 to 4 weeks of therapy, the dosage may be increased to one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. The maximum dose is one tablet of losartan potassium and hydrochlorothiazide 100 mg/25 mg once daily. Losartan potassium and hydrochlorothiazide tablets are not recommended as initial therapy in patients with hepatic impairment (see WARNINGS, Impaired Hepatic Function) because the appropriate 25 mg starting dose of losartan cannot be given. It is also not recommended for use as initial therapy in patients with intravascular volume depletion (e.g., patients treated with diuretics, see WARNINGS, Hypotension— Volume-Depleted Patients).
Hypertensive Patients with Left Ventricular Hypertrophy
Treatment should be initiated with losartan potassium tablets 50 mg once daily. Hydrochlorothiazide 12.5 mg should be added or losartan potassium and hydrochlorothiazide tablets, USP 50 mg/12.5 mg substituted if the blood pressure reduction is inadequate. If additional blood pressure reduction is needed, losartan potassium tablets 100 mg and hydrochlorothiazide 12.5 mg or losartan potassium and hydrochlorothiazide tablets, USP 100 mg/12.5 mg may be substituted, followed by losartan potassium tablets 100 mg and hydrochlorothiazide 25 mg or losartan potassium and hydrochlorothiazide tablets, USP 100 mg/25 mg. For further blood pressure reduction other antihypertensives should be added (see CLINICAL PHARMACOLOGY, Pharmacodynamics and Clinical Effects, Losartan Potassium, Reduction in the Risk of Stroke).
Losartan potassium and hydrochlorothiazide tablets, USP may be administered with other antihypertensive agents.
Losartan potassium and hydrochlorothiazide tablets, USP may be administered with or without food.