Losacar-H Mechanism of Action

Pharmacology: Losartan antagonizes the effect of angiotensin II (vasoconstriction and aldosterone secretion) by blocking the angiotensin II receptor (AT1 receptor) in vascular smooth muscle and the adrenal gland, producing decreased BP; hydrochlorothiazide inhibits reabsorption of sodium and chloride in ascending loop of Henle and early distal tubules.
Pharmacokinetics: It is readily absorbed from the gastro-intestinal tract following oral administration, with an oral bioavailability of about 33%. It undergoes first pass metabolism to form an active carboxylic acid metabolite, E-3174(EXP-3174), which has greater pharmacological activity than losartan, and some inactive metabolites. Peak plasma concentrations of losartan & E-9174 occur 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. It is excreted in the urine and in the feces via bile, as unchanged drug metabolites.