Primary Prophylaxis of Cerebral Toxoplasmosis in HIV-Infected Patients

Inclusion Criteria Concurrent Medication: Allowed: * Zidovudine (AZT), didanosine (ddI), dideoxycytidine (ddC), erythropoietin (Eprex), other agents granted Treatment IND or expanded access status. * Investigational triazoles. * Pentamidine for primary prophylaxis of Pneumocystis carinii pneumonia (PCP). Patients with the following are excluded: * History of cerebral toxoplasmosis or toxoplasmosis infection in any other organ or tissue. * Focal neural abnormalities (except peripheral neuropathy) or mass lesions on a previous computerized tomography (CT) scan or magnetic resonance image (MRI), unless subsequent workup rules out toxoplasmosis, in which case abnormalities must have been stable for at least 2 months. * Known or suspected allergy or severe intolerance to study drugs. Patients must have: * Positive toxoplasma serology. * HIV infection. * Willingness and ability to comply with the protocol and capability of giving written informed consent. Exclusion Criteria Co-existing Condition: Patients with the following conditions or symptoms are excluded: * Current diagnosis of cerebral toxoplasmosis or toxoplasmosis infection in any other organ or tissue. * Known or suspected allergy or severe intolerance to study drugs. Concurrent Medication: Excluded: * Anticoagulants. Other antifolates, sulfonamides, fansidar, macrolides, 5-fluorouracil, dapsone, or any other agent with known activity against Toxoplasma gondii.