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.
Am J Health Syst Pharm. 2000;57(13) © 2000 American Society of Health-System Pharmacists
Cite this: Angiotensin II-Receptor Antagonists: An Overview - Medscape - Jul 01, 2000.