| 18182939 |
Mirza FS, Ong P, Collins P, Okamura K, Gerhard-Herman M, Williams GH, Seely EW: Effects of estradiol and the angiotensin II receptor blocker irbesartan on vascular function in postmenopausal women. Menopause. 2008 Jan-Feb;15(1):44-50.
OBJECTIVE: Estradiol and angiotensin receptor blockers have prominent effects on the renin-angiotensin-aldosterone system. The purpose of this study was to determine whether irbesartan, an angiotensin receptor blocker, has a greater effect on vascular function when combined with estradiol, compared with irbesartan alone, in hypertensive postmenopausal women. DESIGN: Fifty-one women were studied while off any antihypertensive medications or hormone therapy at baseline and after randomization to one of four treatment arms for 12 weeks: (1) irbesartan and estradiol, (2) irbesartan and placebo, (3) estradiol and placebo, and (4) placebo/placebo. Estradiol and placebo arms served as control groups. Blood pressure, brachial reactivity, aldosterone, insulin, glucose, 24-hour urinary catecholamines, urinary sodium, and creatinine were measured. Fisher's exact test was used for comparison of differences in blood pressure in the treatment arms. Paired t test and analysis of variance were also performed for within- and between-group analysis. RESULTS: A significantly larger number of women in the irbesartan and estradiol group had a decrease of 5 mm Hg or more in both systolic and diastolic blood pressures (P < 0.05) compared with irbesartan alone group. Forearm vascular reactivity was increased significantly compared with baseline (P < 0.05), and there was a significant decrease in the serum aldosterone level after treatment compared with baseline (P < 0.05) in the irbesartan and estradiol combination group. Fasting glucose and insulin, urinary sodium/creatinine ratio, and catecholamines were similar at each time point. CONCLUSIONS: The results suggest that irbesartan and estradiol, when used in combination, may cause a greater lowering of blood pressure in postmenopausal hypertensive women. This effect may be mediated via increased vasodilation and lower aldosterone levels. These results warrant further testing in larger clinical trials. |
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