Treatment of excessive polycythemia of high altitude with respiratory stimulant drugs.

Abstract

Excessive polycythemia of high altitude is characterized by excessive hypoxemia due, in part, to hypoventilation. Because progestational agents have stimulant effects on ventilation, we evaluated the effect of medroxyprogesterone acetate on 17 patients with excessive polycythemia of high altitude residing at an altitude of 3,100 m. After 10 weeks of therapy with 20 mg of medroxyprogesterone acetate three times per day, the mean ± SE hematocrit decreased in all 17 patients from 60.1 ± 1.6 to 52.1 ± 1.5 per cent (P ± <0.001). Mean resting ventilation increased on medroxyprogesterone acetate from 9.7 ± 0.48 to 11.7 ± 0.32 liter per min (P < 0.001) due to an increase in tidal volume with no systematic effect on breathing frequency. This decreased the ratio of dead space to tidal volume from 42.1 ± 1.6 to 35.7 ± 2.1 per cent (P < 0.01). The arterial Pco2 decreased 4.3 mm Hg on medroxyprogesterone acetate from 32.9 ± 0.8 to 28.6 ± 0.8 mm Hg (P < 0.001); the normal arterial Pco2 at an altitude of 3,100 m is 30.9...