Losartan Potassium is the first orally active angiotensin-II receptor (type-AT1) antagonist. Osartan and its principal active metabolite block the vasoconstrictor and aldosterone secreting effects of angiotensin-II to the AT1 receptor. Hydrochlorothiazide is a thiazide diuretic. Thiazides affect the renal tubular mechanisms of electrolyte reabsorption, directly by increasing sodium excreation. Indirectly, the diuretic action of hydrochlorothiazide reduces plasma volume with consequent increase in plasma renin activity, aldosterone secretion, urinary potassium loss, and decreases in serum potassium. The renin-aldosterone link is mediated by angiotensin II, so co-administration of Losartan tends to reverse the potassium loss associated with Hydrochlorothiazide.
Osartan-HZ Tablet: Each tablet contains Losartan Potassium USP 50 mg and Hydrochlorothiazide BP 12.5 mg.
Osartan-HZ is indicated for the treatment of hypertension.
Hypertension: The usual dose of Osartan-HZ is one tablet daily. Then if necessary increase to two tablets once daily. The maximum dose is two tablets once daily. In general the antihypertensive effect is attained within three weeks after initiation of therapy.
Use in patients with renal impairment: The usual regimens of therapy with Osartan-HZ may be followed as long as the patient's creatinine clearance is > 30ml/min. In patients with more severe renal impairment, loop diuretics are preferred to thiazides. In that case, hydrochlorothiazide is not recommended.
Use in patients with hepatic impairment: The combination of losartan and hydrochlorothiazide is not recommended for titration in patients with hepatic impairment.
Severe hypertension: The starting dose of Osartan-HZ for initial treatment of severe hypertension is one tablet once daily. For patients who do not respond adequately to this dose after 2 to 4 weeks of therapy, the dosage may be increased to two tablets once daily. The maximum dose is two tablets once daily.
Osartan-HZ may be administered with other antihypertensive agents. Osartan-HZ may be administered with or without food.
Osartan-HZ is contraindicated in patients who are hypersensitive to any component of this product. Because of the hydrochlorothiazide component, this product is contraindicated in patients with anuria or hypersensitivity to other sulfonamide-derived drugs.
Periodic determination of serum electrolytes to detect possible electrolyte imbalance should be performed at appropriate intervals.
In diabetic patients dosage adjustments of insulin or oral hypoglycemic agents may be required. Hyperglycemia may occur with thiazide diuretics.
If progressive renal impairment becomes evident, consider withholding or discontinuing diuretic therapy.
Increase in cholesterol and triglyceride levels may be associated with thiazide diuretic therapy.
In clinical trials with losartan potassium and hydrochlorothiazide, no adverse experiences have been observed. The overall incidence of adverse experiences reported with the combination is comparable to placebo.
Losartan potassium: No significant drug-drug pharmacokinetic interactions have been found in studies with hydrochlorothiazide, digoxin, warfarin, cimetidine and phenobarbitol.
Hydrochlorothiazide: Alcohol, barbiturates, or narcotics- Potentiation of orthostatic hypotension may occur. Antidiabetic drugs (oral agents and insulin)- Dosage adjustment of the antidiabetic drug may be required. Other antihypertensive drugs- Additive effect or potentiation. Cholestyramine and colestipol resins- Absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Corticosteroids, ACTH- Intensified electrolyte depletion, particularly hypokalemia. Skeletal muscle relaxants, tubocurarine- Possible increased responsiveness to the muscle relaxant. Lithium -Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity. NSAID can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics.
Use in pregnancy: Not recommended.
Use in pediatric: Safety and effectiveness in pediatric patients have not been established.
Osartan-HZ Tablet: Each box contains 30's tablets in blister pack.
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