The effect of ventilatory stimulation with medroxyprogesterone on exercise performance and the sensation of dyspnoea...

Seven male patients with hypercapnic chronic bronchitis were given the ventilatory stimulant drug medroxyprogesterone acetate (MPA) 20 mg t.d.s. orally for 4 weeks preceded by a control period of one week. The patients were assessed at the beginning and end of the control period, at 2-weekly intervals while they took the drug and 2 weeks to 5 months after they stopped it. Arterial blood gases, spirometry and a 12-minute walking test were performed on each occasion. During treatment with MPA, arterial Pco2 fell in all patients from a mean control of 50.6 (+/- 1 SEM) mmHg to 44.4 (+/- 1) mmHg (P less than 0.001) and Po2 rose in all patients from a mean control of 53 (+/- 1.9) mmHg to 61 (+/- 3.2) mmHg (P less than 0.05). These effects were achieved without changes in PEFR, FEV1 or FVC. In spite of this, there was no improvement in the sensation of dyspnoea on visual analogue scales at rest or after exercise, and no significant increase in the 12-minute walking distance. The only side effect associated with MPA was slight fluid retention. Ventilatory stimulation with MPA improves arterial blood gases in hypercapnic chronic bronchitis but there is no accompanying improvement in symptoms or exercise tolerance.