The prevention of Pneumocystis carinii pneumonia by pentamidine inhalation

: 167 HIV-positive patients (155 men, 12 women; mean age 31 [18-61] years) with CD4 lymphocyte counts below 250/microliter every 4 weeks received 300 mg pentamidine per aerosol inhalation during out-patient visits, as prophylaxis against Pneumocystis carinii. 89 patients were clinically in the AIDS stage and 33 in the AIDS-related complex (ARC) stage. 29 patients had a lymphadenopathy syndrome, while 16 were asymptomatic. 130 patients received primary prophylaxis, while 37 who had previously had an attack of Pneumocystis carinii pneumonia were given pentamidine as secondary prophylaxis. During a mean observation period of 8 months three patients developed Pneumocystis carinii pneumonia (1.7%): their CD4 lymphocyte count was under 20/microliters. Pentamidine inhalation reduced the incidence of a first attack of pneumonia to 0.18% per month and recurrence to 0.32% per month. These figures confirm the great effectiveness of primary and secondary prophylaxis with pentamidine inhalation.