A randomized trial of three antipneumocystis agents in patients with advanced human immunodeficiency virus infection.

Background We evaluated the effectiveness of three treatment strategies for the prevention of a first episode of Pneumocystis carinii pneumonia in patients infected with the human immunodeficiency virus (HIV). Methods In an open-label trial, 843 patients with HIV infection and fewer than 200 CD4+ cells per cubic millimeter received zidovudine plus one of three randomly assigned prophylactic agents, beginning with trimethoprim–sulfamethoxazole, dapsone, or aerosolized pentamidine and followed by a defined sequence of other drugs to be used in cases of intolerance. Results The estimated 36-month cumulative risks of P. carinii pneumonia were 18 percent, 17 percent, and 21 percent in the trimethoprim–sulfamethoxazole, dapsone, and aerosolized-pentamidine groups, respectively (P = 0.22). The difference in risk among treatment strategies was negligible in patients entering the study with 100 or more CD4+ lymphocytes per cubic millimeter. In those entering with fewer than 100 CD4+ cells per cubic millimeter, the...