A Randomized Prospective Study of Pyrimethamine Therapy for Prevention of Toxoplasmic Encephalitis in HIV-Infected Individuals With Serologic Evidence of Latent Toxoplasma Gondii Infection

Toxoplasmic encephalitis is a major cause of illness and death in AIDS patients. Standard treatment for toxoplasmic encephalitis is to combine pyrimethamine and sulfadiazine. Continuous treatment is necessary to prevent recurrence of the disease, but constant use of pyrimethamine/sulfadiazine is associated with toxicity. Clindamycin has been shown to be effective in treatment of toxoplasmic encephalitis in animal studies. This study evaluates pyrimethamine as a preventive treatment against toxoplasmic encephalitis (per 3/26/91 amendment, clindamycin arm was discontinued). Patients are randomized to receive pyrimethamine or placebo three times a week. All patients must be on aerosolized pentamidine, trimethoprim / sulfamethoxazole (T/S), or dapsone for Pneumocystis carinii pneumonia prophylaxis. Patients will be evaluated bi-weekly for the first month and every other month thereafter for at least 24 months.