Treatment of central nervous system toxoplasmosis with pyrimethamine/sulfadiazine combination in 35 patients with the acquired immunodeficiency syndrome. Efficacy of long-term continuous therapy.

Thirty-five patients with the acquired immunodeficiency syndrome (AIDS) and central nervous system toxoplasmosis, seen over a 30-month period, were treated with the combination pyrimethamine/sulfadiazine. All patients had clinical and computed tomographic scan findings consistent with active neurotoxoplasmosis. Mean duration of total therapy was six months. During the first two months of therapy, four patients died of acute neurotoxoplasmosis and 31 showed improvement. Of the 24 patients evaluable for long-term therapy, 14 (58 percent) achieved complete resolution and 10 had late clinical (n = 7) and/or computed tomographic scan (n = 6) sequelae. Six patients experienced 10 relapses, which occurred within six weeks of treatment discontinuation in seven of 10. Reintroduction of the combination led to complete resolution of the relapse in eight cases. These clinical results were correlated with brain anatomic findings in the 15 autopsied cases. Side effects, noted in 25 of 35, were mainly hematologic toxicity (n = 21) and cutaneous rash (n = 12). However, the combination had to be definitively stopped in only two cases and sulfadiazine alone had to be withdrawn in eight other cases. These data suggest that pyrimethamine/sulfadiazine is highly efficacious in neurotoxoplasmosis and that life-long therapy is needed to prevent relapses in patients with AIDS.