Description
Mechanism of Action
Losartan is an angiotensin II receptor antagonist. It selectively and competitively blocks the vasoconstricting and aldosterone-secreting effects of angiotensin II by selectively antagonising its binding to AT1 receptors.
Onset: 6 hr.
Absorption: Readily absorbed from the GI tract. Bioavailability: 25-33%. Time to peak plasma concentration: Approx 1 hr (losartan); approx 3-4 hr (active metabolite).
Distribution: Volume of distribution: 34 L (losartan); 12 L (active metabolite). Plasma protein binding: >98%.
Metabolism: Metabolised primarily by CYP3A4 and CYP2C9 isoenzymes to active carboxylic acid metabolite (E-3174).
Excretion: Via urine (approx 4% as unchanged drug; approx 6% as active metabolite); faeces (as unchanged drug and metabolites). Terminal elimination half-life: Approx 1.5-2.5 hr (losartan); approx 3-9 hr (E-3174).
MIMS Class
Angiotensin II Antagonists
ATC Classification
C09CA01 – losartan; Belongs to the class of angiotensin II antagonists. Used in the treatment of cardiovascular disease.;
