Efficacy and effects on pulmonary function tests of weekly 600 mg aerosol pentamidine as prophylaxis against Pneumocystis carinii pneumonia.

A prospective study was designed to evaluate the efficacy and effects on pulmonary function tests of weekly 600 mg aerosolised pentamidine as prophylaxis against Pneumocystis carinii pneumonia (PCP) amongst two groups of patients infected with the human immunodeficiency virus. Group 1 (primary prophylaxis) consisted of patients with either diseases indicative of AIDS other than PCP or whose absolute CD4 positive lymphocyte count was below 200/mm3, and Group 2 (secondary prophylaxis) comprised patients with previous proven episodes of PCP. Fifty-five patients (30-Group 1, 25-Group 2) were studied over a period of 36 months, and no patients reached a study end point of either relapse or death due to PCP after a mean duration of treatment of 14.9 months (range 9-36 months). There were no significant differences between the pulmonary function tests (forced expiratory volume in the first second, forced vital capacity and carbon monoxide diffusion capacity) performed at the start and end of the study on both groups of surviving patients. Ten patients (18%) reported coughing and eight patients (15%) were documented to have bronchoconstriction, which was found to be preventable by prior administration of disodiumcromoglycate. The results showed that weekly 600 mg aerosolised pentamidine is effective and well tolerated for primary and secondary prophylaxis against PCP without additional adverse effects. Further prospective randomized trials are needed to determine whether doses higher than the current recommended 300 mg monthly dosage of aerosolised pentamidine provide more efficacy before such an alternative prophylactic treatment is generally adopted for patients who cannot tolerate other systemic agents.