Angiotensin II-Receptor Antagonists: An Overview

Raquel Dina and Mahtab Jafari


Am J Health Syst Pharm. 2000;57(13) 

In This Article

Drug Interactions

Of the AT-II-receptor antagonists, only candesartan has any clinically important interactions with digoxin, warfarin, and hydrochlorothiazide. Candesartan may increase serum concentrations of digoxin and may decrease warfarin concentrations; however, there is no apparent change in the International Normalized Ratio.

Losartan is metabolized by the CYP isoenzyme system; however, the effects of potent inhibitors of CYP3A4 and CYP2C9 on losartan pharmacokinetics have not been clinically studied. When administered with losartan, phenobarbital causes a 20% reduction in serum concentrations of losartan and its metabolite, thus reducing its effectiveness. Eprosartan, candesartan, irbesartan, valsartan, and telmisartan are not metabolized by the CYP system.


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