Prevention of Pneumocystis carinii pneumonia and toxoplasmic encephalitis in human immunodeficiency virus infected patients: a clinical approach comparing aerosolized pentamidine and pyrimethamine/sulfadoxine.

The incidence of Pneumocystis carinii pneumonia (PCP) and toxoplasmic encephalitis (TE) was analyzed in 83 human immunodeficiency virus (HIV)-infected patients who inhaled aerosolized pentamidine (AP) either for primary prophylaxis (group Ia) or secondary prophylaxis (group IIa) of PCP. These cohorts were compared with two historical groups of patients who took Fansidar (pyrimethamine/sulfadoxine) for primary prophylaxis (group Ib) or secondary prophylaxis (group IIb) of PCP. The follow-up was 3-41 months (median 8 months). PCP did not occur in group Ia but was seen in 1 patient of group Ib (5%). TE was observed in 3 patients of group Ia (7.3%) and in 1 patient of group Ib (5%). PCP relapses were seen in 5 patients of group IIa (11.9%) and in 3 patients of group IIb (6.9%), whereas TE occurred in 13 patients of group IIa (30.9%) and in 1 patient of group IIb (2.3%). 20.3% of patients with CD4+ counts less than or equal to 100/microliters and only 7.7% of those with CD4+ counts greater than 100/microliters developed toxoplasmosis. In conclusion, Fansidar rather than AP prophylaxis should be recommended for patients with a history of PCP or toxoplasmosis and for all HIV-infected patients with CD4+ counts less than or equal to 100/microliters. In patients with CD4+ lymphocyte counts between 100 and 200/microliters, AP prophylaxis appears appropriate.