Comparative Efficacy and Safety of Olmesartan Versus Losartan in Patients With Hypertension

Abstract

Angiotensin II receptor blockers (ARBs) are the newest class of approved antihypertensive agents and the second class of drugs to exert their primary antihypertensive action by interrupting the renin-angiotensin system. It was a multicenter, randomized, double-blind trial in which efficacy of Olmesartan (20mg once a day) and losartan (50mg once a day) was compared in patients with hypertension. In patients with a cuff diastolic blood pressure (DBP) of ≥100 and ≥115 mm Hg and a mean daytime DBP of ≥90mm Hg and <120mm Hg, as measured by ambulatory blood pressure monitoring. Cuff and ambulatory blood pressures were monitored at baseline and after 8 weeks of treatment. All groups were adults and approximately 62% male, and their mean age was approximately 52 years. In all groups, mean baseline DBP and systolic blood pressure (SBP) were approximately 104 and 157mm Hg, respectively. The reduction of sitting cuff DBP with olmesartan (13.5mm Hg), the primary efficacy variable of this study, was significantly greater than with losartan, enalapril, and quinapril (8.2, 7.9, and 9.9mm Hg, respectively). Reductions of cuff SBP with the four ARBs ranged from 8.4-13.3mm Hg and were not significantly different. The reduction in mean 24-hour DBP with olmesartan (8.5mm Hg) was significantly greater than reductions with losartan and enalapril (6.2 and 5.6mm Hg, respectively) and showed a trend toward significance when compared to the reduction in DBP with quinapril (7.4mm Hg; p=0.087). The reduction in mean 24-hour SBP with olmesartan (12.5mm Hg) was significantly greater than the reductions with losartan and enalapril (9.0 and 8.1mm Hg, respectively) and equivalent to the reduction with quinapril (11.3mm Hg). All drugs were well tolerated. The authors conclude that olmesartan, at its starting dose, is more effective than the starting doses of the other tested drugs in reducing cuff DBP in patients with essential hypertension. KEYWORDS: Essential Hypertension, Enalapril, Losartan, Olmesartan. INTRODUCTION:Angiotensin II receptor blockers (ARBs) are the newest class of approved antihypertensive agents and the second class of drugs to exert their primary antihypertensive action by interrupting the renin-angiotensin system. ARBs prevent the hypertensive effects of angiotensin II by selective blockade of the angiotensin II type 1 (AT1) receptor. Olmesartan is a new ARB that was discovered during a systematic survey of the AT1 binding actions of substituted imidazole-5-carboxylic acids.It is a prodrug that, following oral administration, is rapidly and completely de-esterified in the gut to its active form, in a reaction that is not cytochrome P-450-dependent. This active metabolite, olmesartan, is a potent and selective AT1 receptor antagonist, with no agonist activity. 1,2,3 In healthy subjects, olmesartan has an elimination half-life of 12-18 hours, a value that is comparable to the longest half-lives of ARBs currently in clinical use.

Effects of angiotensin II receptor blockers in the coronary arteries of hypertensive rats: Analysis of elemental distribution using LEXRF

“…These results demonstrated a greater effectiveness of olmesartan in decrease BP when compared with losartan, reaching basically the same values as for the WKY healthy group. These findings are in line with the results of previous works …”