Comparison of trimethoprim-sulfamethoxazole, dapsone, and pentamidine in the prophylaxis of Pneumocystis carinii pneumonia.

STUDY OBJECTIVE

To compare the incidence of Pneumocystis carinii pneumonia (PCP) in patients infected with the human immunodeficiency virus (HIV) receiving one of three prophylactic agents.

DESIGN

Retrospective chart review.

SETTING

A university-affiliated Department of Veterans' Affairs medical center HIV clinic.

PATIENTS

All 200 HIV-infected patients enrolled in the clinic who were prescribed a PCP prophylactic drug during 18 months.

INTERVENTIONS

Patients were administered oral trimethoprim-sulfamethoxazole (TMP-SMX) DS, oral dapsone, or aerosolized pentamidine in a heirarchic fashion. A subset of 110 patients received only one of the prophylaxis regimens for at least 6 months; they were examined separately for the purpose of statistical analysis.

MEASUREMENTS AND MAIN RESULTS

One case of PCP was diagnosed in 1110 patient-months of oral TMP-SMX DS therapy, 6 in 418 patient-months of oral dapsone therapy, and 3 in 164 patient-months of aerosolized pentamidine therapy. In the subset population, the documented incidence of PCP was 0% among 71 TMP-SMX DS-treated patients, 16% among 25 dapsone-treated patients (p < 0.004), and 14% among 14 aerosolized pentamidine-treated patients (p < 0.03). For patients receiving primary prophylaxis, the incidence of PCP was 0% for 58 receiving TMP-SMX, 15% for 20 receiving dapsone (p = 0.015), and 17% for 6 receiving pentamidine (p = 0.094).

CONCLUSION

We believe TMP-SMX DS was more effective than oral dapsone or aerosolized pentamidine in preventing PCP in these HIV-infected patients.