THRICE-WEEKLY COTRIMOXAZOLE IS BETTER THAN WEEKLY DAPSONE-PYRIMETHAMINE FOR THE PRIMARY PREVENTION OF PNEUMOCYSTIS-CARINII PNEUMONIA IN HIV-INFECTED PATIENTS

Objective: To compare the efficacy and safety of two intermittent regi mens for the simultaneous primary prevention of Pneumocystis carinii p neumonia (PCP) and toxoplasmosis in HIV-infected patients. Design: Pro spective randomized open trial. Setting: HIV outpatient clinic of an I nfectious Disease Service and a 1000-bed university teaching hospital. Patients: A total of 166 HIV-infected patients with a CD4 cell count < 200 x 10(6)/l or, a CD4 percentage < 20%, without previous PCP or to xoplasmosis. Intervention: Patients were randomized to oral (1) cotrim oxazole [160 mg trimethoprim (TMP) and 800 mg sulphamethoxazole (SMX)] twice a day on Mondays, Wednesdays and Fridays (n = 81), or (2) dapso ne (100 mg) plus pyrimethamine (25 mg) (DP) once a week (n = 85). Main outcome measures: Clinical and biological evaluation was performed ev ery 30-60 days. End-points were PCP, toxoplasmosis and death. Adverse reactions were considered as defined in the protocol. Results: After a mean follow-up of 380 days, intention-to-treat analysis revealed that DP patients had a higher rate of PCP [13 out of 85 (15.2%) versus thr ee out of 81 (3.7%); P = 0.01]. The cumulative rates of PCP at 12 and 24 months were 5 and 42% for DP patients and 3 and 10% for TMP-SMX pat ients, respectively (Mantel-Cox, P = 0.0007). Of the 29 patients who d ied during follow-up, 14 were in the TMP-SMX group and 15 in the DP gr oup (not significant). Two patients in the TMP-SMX group and three in the DP group developed toxoplasmosis (not significant). Adverse reacti ons were common (66.7% of TMP-SMX patients and 42.4% of DP patients; P = 0.001). However, only 12.3% of TMP-SMX patients and 2.3% of DP pati ents (P = 0.01) had to discontinue therapy because of toxicity. Conclu sions: At the given doses, DP was inferior to TMP-SMX in preventing fi rst episodes of PCP. Although more patients and a longer follow-up are required, the regimens appeared to prevent toxoplasmosis equally well .