SAFETY OF DAPSONE AS PNEUMOCYSTIS-CARINII PNEUMONIA PROPHYLAXIS IN HUMAN IMMUNODEFICIENCY VIRUS-INFECTED PATIENTS WITH ALLERGY TO TRIMETHOPRIM SULFAMETHOXAZOLE/

OBJECTIVE: TO assess the safety of dapsone prophylaxis of Pneumocystis carinii pneumonia (PCP) in patients with prior intolerance td trimeth oprim/sulfamethoxazole (TMP/SMX). METHODS: We conducted a retrospectiv e study in the categorical human immunodeficiency virus out-patient pr ogram of a university hospital. Patients who had filled prescriptions for dapsone at our pharmacy between January 1991 and April 1994 were e valuated and 75 patients were found eligible for analysis. RESULTS: Th e overall incidence of adverse events (AE) in our study cohort was 39% . The most common AEs were anemia (23%) and rash (16%). However, after critical evaluation of each case, only 3 cases of anemia (4%) and 2 c ases of rash (3%) were judged to be ''likely related'' to dapsone. Onl y 5/75 patients (7%) developed the same intolerance to dapsone as prev iously experienced on TMP/SMX, and none of these cases was viewed as ' 'likely related'' to dapsone. A dapsone regimen of 100 mg qd and a pri or episode of PCP were associated with a higher incidence of AEs. Eigh t cases of PCP occurred in spite of dapsone prophylaxis for an inciden ce of 7 cases per 1,000 patient-months. Seven of the cases of PCP occu rred in patients who were receiving secondary prophylaxis. CONCLUSIONS : Given the low incidence of AEs judged to be ''likely related'' to da psone, this drug is a reasonable choice for PCP prophylaxis in patient s with prior AEs to TMP/SMX.