The treatment of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome.

Forty-four episodes of Pneumocystis carinii pneumonia (PCP) occurred in 36 of 70 patients with the acquired immunodeficiency syndrome. Thirty-four patients with 40 episodes of PCP were treated with trimethoprim-sulfamethoxazole. Therapy was successful in 18 episodes (45%), but was unsuccessful in 15 episodes (37.5%). In the latter cases, two patients died within 72 hours; 13, of whom nine died, had therapy changed to pentamidine. In seven additional episodes (17.5%), trimethoprim-sulfamethoxazole was changed to pentamidine due to adverse reactions; all patients survived. Seven patients (26% of survivors) developed recurrent PCP. Twenty-two patients (65%) developed adverse reactions to trimethoprim-sulfamethoxazole, including leukopenia (20), hepatotoxicity (12), fever (eight), rash (six), and immediate reactions (two). Reactions were most common during the second week of therapy. Patients with the acquired immunodeficiency syndrome who have PCP have a high trimethoprim-sulfamethoxazole failure rate, due either to adverse reactions or unresponsive infection. Late recurrence is common.