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

Summary 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 la) 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 lb) or secondary prophylaxis (group IIb) of PCP. The follow-up was 3—41 months (median 8 months). PCP did not occur in group la 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 Ilb (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 < 100/l and only 7.7% of those with CD4⁺ counts > 100/l 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 100/l. In patients with CD4⁺ lymphocyte counts between 100 and 200/l, AP prophylaxis appears appropriate.Abbreviations AIDS acquired immunodeficiency syndrome - AP aerosolized pentamidine - FDA Food and Drug Administration - HIV human immunodeficiency virus - IgG immunoglobulin G - PCP Pneumocystis carinii pneumonia - TE toxoplasmic encephalitis - TMP/SMX trimethoprim/sulfamethoxazole