A Comparison of Atovaquone and Pentamidine in the Prevention of Pneumocystis Carinii Pneumonia in HIV-Infected Patients Who Cannot Take TMP/SMX

To assess whether high dose or low dose atovaquone suspension is more effective than aerosolized pentamidine as prophylaxis against Pneumocystis carinii pneumonia (PCP) in high-risk HIV-infected patients. To compare the safety of chronic administration of the three regimens in patients with advanced HIV disease. To determine the relationship between steady state atovaquone plasma concentrations and prophylactic efficacy against PCP.

Patients are randomized to receive oral atovaquone at 1 of 2 doses once daily or aerosolized pentamidine once every 4 weeks. Treatment continues until 18 months after the last patient is enrolled. Patients are stratified into primary or secondary prophylaxis strata based on prior occurrence of a PCP episode.