Angiotensin II-receptor antagonists: An overview

Angiotension II (AT-II)-receptor antagonists are reviewed. Research focused on blocking the renin-angiotensin system (RAS) led to the discovery of angiotensin-converting-enzyme (ACE) inhibitors, which are effe ctive in the treatment of hypertension but are associated with a high frequ ency of cough and other adverse effects. AT-II-receptor antagonists were de veloped as agents that would more completely block the RAS and thus decreas e the adverse effects seen with ACE inhibitors. AT-II-receptor antagonists include losartan, valsartan, irbesartan, candesartan, eprosartan, telmisart an, and tasosartan. Several clinical trials have demonstrated that AT-II-re ceptor antagonists are as effective as calcium-channel blockers, beta-block ers, and ACE inhibitors in the treatment of hypertension and induce fewer a dverse effects. The adverse effects of AT-II-receptor antagonists-dizziness , headache, upper-respiratory-tract infection, cough, and gastrointestinal disturbances-occur at about the same rate as with placebo. Of the AT-II-rec eptor antagonists, only candesartan has any clinically important interactio ns with digoxin, warfarin, and hydrochlorothiazide. All available AT-II-rec eptor antagonists seem to be equally effective in reducing both systolic an d diastolic blood pressure, and they are comparable in cost. Currently, AT- ii-receptor antagonists are used either as monotherapy in patients who cann ot tolerate ACE inhibitors or in combination with other antihypertensive ag ents. Angiotensin II-receptor antagonists are well tolerated and are as effective as ACE inhibitors in decreasing blood pressure.