Study objectives: The degree and duration of respiratory stimulation of medroxyprogesterone acetate (MPA) in postmenopausal women.
Design: A placebo-controlled single-blind trial.
Setting: University hospital in Turku, Finland.
Patients: Fourteen postmenopausal women with permanent or previous episodic hypercapnic or hypoxemic respiratory failure.
Interventions: A 12-week trial including 14-day treatment periods with placebo and MPA (60 mg daily) and a 6-week follow-up.
Results: Thirteen of 14 patients completed the trial. The mean (+/- SD) PaCO2 at baseline was 42.8+/-4.5 mm Hg and the mean PaO2 was 71.2+/-9.0 mm Hg. The average reduction of PaCO2 was 6.3 mm Hg (14.7%, p < 0.001) on MPA and 3.0 mm Hg (6.1%, p = 0.001) after a 3-week washout. At 6 weeks after MPA, the PaCO2 had returned to baseline. The mean changes in PaO2 (+6.0+/-18.0 mm Hg on MPA and +3.8+/-22.5 mm Hg after a 3-week washout) were not significant. The PaO2/PaCO2 ratio increased, and bicarbonate and base excess decreased (p < 0.001) on MPA but not during washout. The systolic BP did not change on MPA but decreased on average 14.8+/-15.0 mm Hg (p = 0.016) after a 3-week washout. The diastolic BP remained unchanged.
Conclusions: Our results suggest that postmenopausal women with chronic respiratory insufficiency consistently improve on MPA at a dose of 60 mg daily for 14 days. Lower PaCO2 is sustained for at least 3 weeks after cessation of MPA. The sustained effects in gas exchange and favorable after-effects in BP warrant further studies into the therapeutic efficacy and possible benefits of MPA pulse therapy.