A comparison of the effectiveness of three regimens in the prevention of Pneumocystis carinii pneumonia in human immunodeficiency virus-infected patients.

BACKGROUND

Pneumocystis carinii pneumonia (PCP) is a major cause of morbidity and the leading cause of death in patients with the acquired immunodeficiency syndrome. The prevention of the occurrence and recurrence of PCP is a cornerstone in the treatment of patients infected with the human immunodeficiency virus. There are few studies comparing PCP prophylactic regimens.

METHODS

The efficacy of three regimens for prophylaxis against PCP was assessed in a retrospective chart review of 211 human immunodeficiency virus-infected patients at risk for the disease. Over the course of the 2-year study period, 133 patients were prescribed trimethoprim-sulfamethoxazole (one double-strength tablet twice a day, thrice weekly) for a mean of 7.4 months (range, 1 to 25 months). Seventy-seven patients received dapsone (50 mg daily) for a mean of 5.7 months (range, 1 to 23 months), and 125 patients received aerosolized pentamidine (300 mg via nebulizer once monthly) for a mean of 9.3 months (range, 1 to 21 months). The majority of patients (62%) received primary prophylaxis; 38% had one or more previous episodes of PCP; and 73% were receiving concomitant antiretroviral therapy.

RESULTS

Pneumocystis carinii pneumonia did not develop in any patient receiving trimethoprim-sulfamethoxazole in 981 patient-months. Five patients receiving dapsone for 437 patient-months and 17 patients receiving aerosolized pentamidine for 1166 patient-months developed PCP. Fifty-six percent of the trimethoprim-sulfamethoxazole group and 55% of the dapsone group changed drug due to adverse reactions, while only 2% in the aerosolized pentamidine group required drug change.

CONCLUSION

Despite its adverse reaction profile, trimethoprim-sulfamethoxazole is the most effective agent to prevent the occurrence and recurrence of PCP.