Angiotensin II-receptor antagonists: an overview.

Angiotensin 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 effective in the treatment of hypertension but are associated with a high frequency of cough and other adverse effects. AT-II-receptor antagonists were developed as agents that would more completely block the RAS and thus decrease the adverse effects seen with ACE inhibitors. AT-II-receptor antagonists include losartan, valsartan, irbesartan, candesartan, eprosartan, telmisartan, and tasosartan. Several clinical trials have demonstrated that AT-II-receptor antagonists are as effective as calcium-channel blockers, beta-blockers, and ACE inhibitors in the treatment of hypertension and induce fewer adverse 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. [corrected]. All available AT-II-receptor antagonists seem to be equally effective in reducing both systolic and diastolic blood pressure, and they are comparable in cost. Currently, AT-II-receptor antagonists are used either as monotherapy in patients who cannot tolerate ACE inhibitors or in combination with other antihypertensive agents. Angiotensin II-receptor antagonists are well tolerated and are as effective as ACE inhibitors in decreasing blood pressure.