Study objectives: The degree and duration of
respiratory stimulation of medroxyprogesterone acetate (MPA) in
Design: A placebo-controlled
Setting: University hospital in
Patients: Fourteen postmenopausal
women with permanent or previous episodic hypercapnic or hypoxemic
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.