Losartan carboxylic acid is a physiologically active metabolite of losartan (Item No.
10006594), produced by cytochrome P450 isoforms in the liver.
1 Like the parent compound, losartan carboxylic acid is a potent AT
1 antagonist (K
is = 0.57 and 0.67 nM for rat and human forms, respectively), producing a depressor response and vasodilatation.
2,3,4 When administered intravenously, losartan carboxylic acid is more potent and has a longer duration of action than losartan.
4 However, the metabolite has very low oral bioavailability.
4 Losartan, but not its metabolite, inhibits platelet aggregation
in vitro.
5