Olmesartan compared with other angiotensin II receptor antagonists: Head-to-head trials

Background: Drugs that block the renin-angiotensin system represent one of the most significant therapeutic interventions available for the treatment of hypertension. The angiotensin II receptor antagonists (AIIRAs), also known as sartans, are one such class of drugs that block the effects of angiotensin II by antagonizing the angiotensin II type 1 receptor. Olmesartan is the newest member of this class.Objective: The present article reviews 3 head-to-head trials directly comparing the antihypertensive efficacy of olmesartan with that of 4 other AURAS, at recommended maintenance doses, already in clinical use for the treatment of hypertension.Results: In the first study, olmesartan 10 mg/d was compared with losartan 50 mg/d in 316 patients with mild to moderate hypertension (mean baseline diastolic blood pressure DBP], 95–114 mm Hg). Dosage was doubled at week 4 and hydrochlorothiazide was added at week 12 if blood pressure response was inadequate. Olmesartan was significantly more effective than losartan with respect to the reduction in blood pressure at weeks 2, 4, and 12, and to the responder rate at weeks 2 and 4 (with the starting dose of the respective drug). In a second study, olmesartan 20 mg/d was shown to be significantly more effective than losartan 50 mg/d, valsartan 80 mg/d, and irbesartan 150 mg/d in 588 patients with mild to moderate hypertension (mean sitting baseline DBP, 100–115 mm Hg) (P ⩽ 0.05). At week 2, the reduction in blood pressure observed with olmesartan was significantly greater than that of the comparator treatments (P ⩽ 0.05). The superiority of olmesartan was maintained at week 8. The third study involved 643 evaluable patients with moderate to severe hypertension (mean DBP, 100–120 mm Hg; mean systolic blood pressure, >150 mm Hg). Olmesartan 20 mg/d was more effective than candesartan 8 mg/d in lowering 24-hour blood pressure at week 8 (P ⩽ 0.05). Most of this treatment effect was evident after only 1 or 2 weeks, with greater reductions in blood pressure compared with candesartan.Conclusions: These data indicate that, at the doses studied, olmesartan is more effective than other AIIRAs tested at their recommended doses, in terms of reduction of cuff or 24-hour ambulatory blood pressure, in patients with essential hypertension. These differences in blood pressure reduction between these agents may be clinically relevant and have important long-term implications. Additional studies will further define the role of olmesartan in the management of cardiovascular diseases, such as atherosclerosis.