Transdermal oestrogen reduces daytime blood pressure in hypertensive women [see comment]

The aim of this study was to investigate the acute effects of transdermally administered 17-beta-oestradiol on ambulatory blood pressure (BP) in hypertensive, postmenopausal women. Thirteen postmenopausal women with ongoing treatment for hypertension were included in this placebo-controlled, double-blind cross-over study. Ambulatory recordings of BP and heart rate were performed during 24 h on two occasions, separated by at least 1 week, after application of a patch containing either 100 microg per 24 h 17-beta-oestradiol or placebo. Serum oestradiol was increased (P<0.001) during active treatment (139.2 +/- 21.1 pg/ml) compared with the baseline postmenopausal levels recorded during placebo (40.5 +/- 2.2 pg/ml). No rise in BP was found in office BP or during ambulatory recordings. Daytime BP pressure was acutely reduced by approximately 3 mm Hg during the 24 h of treatment with oestrogen (SBP n.s., DBP P<0.05), without any change in heart rate. Nocturnal dipping in SBP and DBP was present during placebo conditions, and there were no signs of an increase in dipping during treatment with 17-beta-oestradiol. This study supports previous evidence that hormone replacement therapy is safe in hypertensive women. The data in the present study also imply an acute, but small reduction of daytime BP due to transdermal oestrogen in hypertensive, postmenopausal women. Furthermore oestrogen did not blunt or increase the dipping phenomena during the night in these women.