Long-term follow-up of patients with AIDS on maintenance therapy for toxoplasmosis.

To assess potential interactions of multiple drug regimens administered to patients with AIDS for toxicity and efficacy, we reviewed the charts of 35 patients on maintenance therapy for toxoplasmosis. Seven relapses of toxoplasmosis occurred in 6 of 35 (17%) patients, and seven episodes of pneumocystosis occurred in 6 of 35 (17%) patients. Four relapses of toxoplasmosis and 5 relapses of pneumocystosis were seen in 20 patients treated with pyrimethamine/clindamycin; 2 relapses of toxoplasmosis and 2 relapses of pneumocystosis were seen in 11 patients treated with pyrimethamine alone, and 1 relapse of toxoplasmosis was seen in 13 patients treated with pyrimethamine/sulfadiazine. Adverse effects were related to pyrimethamine in 10 patients, to clindamycin in 7 patients, and to sulfadiazine in 8 patients. These results must be compared with those of prospective trials to determine the efficacy and safety of various maintenance regimens.