Natrasol

Each film-coated tablet contains Losartan Potassium 50 mg or 100 mg.

Pharmacology: Pharmacokinetics: Losartan is readily absorbed from the gastrointestinal tract after oral doses, but undergoes substantial first-pass metabolism resulting in a systemic bioavailability of about 33%. It is metabolized to an active carboxylic acid metabolite E-3174 (EXP-3174), which has greater pharmacological activity than losartan; some inactive metabolites are also formed. Metabolism is primarily by cytochrome P450 isoenzymes CYP2c9 and CYP3A4. Peak plasma concentrations of losartan and E-3174 occur about 1 hour and 3 to 4 hours, respectively, after an oral dose. Both losartan and E-3174 are more than 98% bound to plasma proteins. Losartan is excreted in the urine, and in the faeces via bile, as unchanged drug and metabolites. About 4% of an oral dose is excreted unchanged in urine and about 6% is excreted in urine as the active metabolite. The terminal elimination half-lives of losartan and E-3174 are about 1.5 to 2.5 hours and 3 to 9 hours, respectively.

Used in the management of hypertension, heart failure, and in myocardial infarction.

In hypertension the usual dose is 50 mg once daily. The maximum effect is achieved in about 3 to 6 weeks after initiating treatment. The dose may be increased, if necessary to 100 mg daily in one or two divided doses. An initial dose of 25 mg once daily is suggested for the elderly over 75 years-of-age, and for patients with moderate to severe renal impairment (creatinine clearance less than 20 mL per minute), or intravascular fluid depletion. A reduced dose should also be considered for patients with hepatic impairment.

Losartan is contraindicated in pregnancy and breast feeding. It should be used with caution in patients with renal artery stenosis. Reduced doses may be required in patients with renal impairment and should be considered in patients with hepatic impairment. Patients with volume depletion (for example those who have received high-dose diuretic therapy) may experience hypotension, which may be minimized by initiating treatment with a low dose of losartan. Since hyperkalemia may occur, serum-potassium concentrations should be monitored, especially in the elderly and patients with renal impairment, and the concomitant use of potassium-sparing diuretics should be avoided.

Adverse effects of losartan have been reported to be usually mild and transient, and include dizziness, headache, and dose-related orthostatic hypotension. Hypotension may occur particularly in patients with volume depletion (for example those who have received high-dose diuretics). Impaired renal function and rarely, rash, urticaria, pruritus, angioedema, and raised liver enzyme values may occur. Hyperkalaemia, myalgia and arthralgia have been reported. Losartan appears less likely than ACE inhibitors to cause cough. Other adverse effects that have been reported with Angiotensin II receptor anatagonists include respiratory-tract disorders, back pain, gastrointestinal disturbances, fatigue, and neutropenia. Rhabdomyolysis has been reported rarely.

Store at temperatures not exceeding 30°C.

Angiotensin II Antagonists

C09CA01 - losartan ; Belongs to the class of angiotensin II receptor blockers (ARBs). Used in the treatment of cardiovascular disease.

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