Composition
Each Amosar® tablet contains: Losartan Potassium ………….. 25 mg.
Description
Losartan Potassium (Amosar®) is the first orally active angiotensin II receptor antagonist available for the treatment of hypertension.
Properties
Amosar®(Losartan Potassium) is an angiotensin II receptor (type AT1) antagonist antihypertensive which acts by blocking the actions of angiotensin II of renin-angiotensin-aldosterone system.
The drug and its active metabolite selectively block the vasoconstrictor and aldosterone secreting effects of angiotensin II by selectively antagonising the binding of angiotensin II to AT1 receptors.
Neither Losartan nor its metabolite inhibits ACE (kininase II); this could explain that losartan therapy is comparable to placebo in regard to lack of cough as a side effect known to be experienced with the ACE inhibitors use.
Losartan is readily absorbed from the gastrointestinal tract following oral administration, with an oral bioavailability of about 33%. It undergoes first pass metabolism in the liver to form an active carboxylic acid metabolite E-3174, which has greater pharmacological activity than losartan, and some inactive metabolites. Peak plasma concentrations of losartan and E-3174 occur about 1 h. and 3 to 4 h., 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 feces via bile, as unchanged drug and metabolites. Following oral dosing about 35% of the dose is excreted in the urine and about 60% in the feces. The terminal elimination half-lives of losartan and E-3174 are about 1.5 to 2.5 h. and 3 to 9 h., respectively.
Indications
All types of hypertension.
Precautions
Patients who are intravascularly volume depleted, renal artery stenosis. Monitor serum potassium concentrations especially in elderly patients or those with renal impairment. Avoid concomitant use of potassium sparing diuretics.
Drug interactions
- Other antihypertensives: Potentiate the hypotensive effect of
losartan. - Potassium sparing diuretics, Potassium supplements: Risk of
hyperkalaemia. - NSAIDs: May blunt hypotensive effect of losartan.
- Cytochrome P450 inhibitors like ketoconazole: Increase in
AUC of losartan by 18% but has no effect on its active metabolite. - Phenobarbital: Results in 20% reduction in AUC of losartan and
its active metabolite.
Dosage
The recommended starting dose of Amosar® is 50 mg once daily. 25 mg is advised in patients with hepatic dysfunction or volume depletion.
If the antihypertensive response is not satisfactory, an increase in dose or twice daily dose may give the desired response.
Usual total daily dose range is 25 –100 mg.
No initial dosage adjustment is necessary in the elderly and in patients with mild to moderate renal impairment.
How Supplied
Strips of 10 tablets in packs of 1 strip.
Keep all medicaments out of reach of children
Product of: AMOUN PHARMACEUTICAL CO. El-Obour City, Cairo, Egypt. ATC Code: C09CA01