High-dose nifurtimox for arseno-resistant Trypanosoma brucei gambiense sleeping sickness: an open trial in central Zaire.

Thirty patients with arseno-resistant Trypanosoma brucei gambiense sleeping sickness were treated with high-dose nifurtimox (30 mg/kg/d for 30 d). During treatment, the cerebrospinal fluid (CSF) white blood cell (WBC) count decreased in all patients except one (mean CSF WBC count before nifurtimox: 117/mm3; after nifurtimox: 25/mm3), and trypanosomes disappeared from the CSF of all 9 patients in whom parasites had been demonstrated before nifurtimox. Among 25 patients seen at least once after treatment, 9 (36%) have relapsed so far. High-dose nifurtimox was significantly toxic: one patient died during treatment and 8 others developed adverse neurological effects. High-dose nifurtimox seems more effective than the previously used regimen (15 mg/kg/d for 60 d), but at the expense of significant toxicity.