Effects of drospirenone/17-beta estradiol on blood pressure and potassium balance in hypertensive postmenopausal women.

Background: Drospirenone (DRSP) is a novel progestin with aldosterone receptor antagonist activity developed for hormone therapy as DRSP /17-beta estradiol (DRSP/E2). Because of a significant aldosterone antagonist activity, we studied the effects of DRSP/E2 on serum potassium (K) and blood pressure (BP) in hypertensive postmenopausal women with and without diabetes mellitus.
Methods: This was a multicenter trial in postmenopausal women 44 to 70 years of age, either with type 2 diabetes mellitus (n = 82) or without type 2 diabetes mellitus (n = 148) and using an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor antagonist. Patients were randomized to 28 days of DRSP/E2 or placebo. Study endpoints were the number and percentage subjects who developed hyperkalemia (K >or= 5.5 mEq/L) and changes from baseline in clinic systolic and diastolic BP. To increase the likelihood of unmasking hyperkalemia, the nondiabetic group was also administered ibuprofen for 5 days.
Results: There were no statistical differences in the overall number and percentage of subjects with hyperkalemia for DRSP/E2 versus placebo. No subject had symptoms or electrocardiographic changes related to hyperkalemia. Blood pressure was reduced by -8.6/-5.8 mm Hg in patients receiving DRSP/E2 versus -3.7/-2.9 mm Hg in those receiving placebo (P < .01 for both SBP and DBP).
Conclusions: In hypertensive postmenopausal women, treatment with DRSP/E2 was not associated with a greater incidence of hyperkalemia than with placebo in patients with and without type 2 diabetes mellitus and concomitant use of ACE inhibitors, angiotensin receptor antagonists, or ibuprofen. Furthermore, DRSP/E2 was found to have a significant antihypertensive effect in this high-risk population.