Objective: To evaluate the endocrinologic changes associated with, and possibly responsible for, prolonged ventilatory improvement after short-term medroxyprogesterone acetate (MPA) in chronic respiratory failure.
Methods: Fourteen postmenopausal women with permanent or previous episodic hypercapnic or hypoxemic respiratory failure were enrolled in a placebo-controlled, 12-week, single-mask trial including 14-day treatment periods with placebo and MPA (60 mg daily) and a 6-week follow-up. We evaluated the duration of MPA-induced alterations on serum concentrations of progesterone, estradiol, testosterone, FSH, LH, sex hormone-binding globulin (SHBG), and prolactin. Hormones were measured four times: at baseline, after 14 days with MPA, and during the washout on days 21 and 42.
Results: With MPA, FSH decreased 42.7% (P <.001, 95% confidence interval [CI] -54.2, -31.6), LH 62.1% (P <.01; 95% CI -81. 0, -32.6), and SHBG 58.1% (P <.001; 95% CI -63.0, -43.9). Luteinizing hormone remained decreased (-28.7%; P <.01; 95% CI -42.0, -14.2) at the 3-week washout, whereas FSH and SHBG were back to pretreatment levels. Prolactin had a borderline initial increase of 23.5% (P =.097; 95% CI -3.5, 50.5) with MPA and a significant increase at the 3-week (31.9%; P <.05; 95% CI 1.0, 62.9) and 6-week (26.4%; P <.05; 95% CI 4.4, 48.3) washouts.
Conclusion: Medroxyprogesterone acetate 60 mg daily for 2 weeks has both immediate (FSH, LH, and SHBG), prolonged (LH), and rebound endocrinologic (prolactin) effects up to 6 weeks after treatment. The MPA-induced widespread endocrine aftereffects could explain the earlier reported prolonged ventilatory improvement.