Objective: This study was designed to compare with placebo the dose-response effect of cyclical doses of the C21 progestogen, medroxyprogesterone acetate (MPA) on blood pressure (BP) when administered to normotensive postmenopausal women receiving a fixed mid-range daily dose of conjugated equine oestrogen (CEE).
Materials and methods: Twenty normotensive postmenopausal women (median age 53 years) participated in the study which used a double-blind crossover design. There were four randomised treatment phases, each of 4 weeks duration. The four blinded treatments were MPA 2.5 mg, MPA 5 mg, MPA 10 mg and matching placebo, taken for the last 14 days of each 28 day treatment cycle. CEE 0.625 mg was also administered once daily as open labelled tablets to all subjects throughout the study. Clinic BP was measured weekly with the mean values of weeks 3 and 4 of each phase used for analysis. Ambulatory BP was performed in the final week of each phase.
Results: Compared with the placebo phase, end of phase clinic BP was unchanged by any of the progestogen treatments. There was a dose-dependent decrease in ambulatory daytime diastolic and mean arterial BP with the progestogen treatments compared with placebo (P < 0.05).
Conclusion: In a regimen of postmenopausal hormone replacement therapy with a fixed mid-range daily dose of CEE combined with a cyclical regimen of a C21 progestogen spanning the current clinical dose range, the progestogen has either no effect or a small dose-dependent reduction in clinic and ambulatory BPs over one treatment cycle.