Adverse Events Associated with Nifurtimox Treatment for Chagas Disease in Children and Adults

Nifurtimox (NF) is one of the only two drugs currently available for Chagas disease (ChD) treatment. However, data on NF safety are scarce, and many physicians defer or refuse NF treatment because of concerns about drug tolerance. In a retrospective study of adverse drug reactions (ADRs) associated with NF treatment of ChD, children received NF doses of 10 to 15 mg/kg/day for 60 to 90 days, and adults received 8 to 10 mg/kg/day for 30 days. A total of 215 children (median age, 2.6 years; range, 0 to 17 years) and 105 adults (median age, 34 years; range, 18 to 57 years) were enrolled. Overall, 127/320 (39.7%) patients developed ADRs, with an incidence of 64/105 adults and 63/215 children (odds ratio [OR] = 3.7; 95% confidence interval [CI], 2.2 to 6.3). We observed 215 ADRs, 131 in adults (median, 2 events/patient; interquartile range for the 25th to 75th percentiles [IQR_25-75], 1 to 3) and 84 in children (median, 1 event/patient; IQR_25-75 = 1 to 1.5) (P_adjusted < 0.001). ADRs were mainly mild and moderate. Severe ADRs were infrequent (1.2% in children and 0.9% in adults). Nutritional, central nervous, and digestive systems were the most frequently affected, without differences between groups. Treatment was discontinued in 31/320 (9.7%) patients without differences between groups. However, ADR-related discontinuations occurred more frequently in adults than in children (OR = 5.5, 95% CI = 1.5 to 24). Our study supports the safety of NF for ChD treatment. Delaying NF treatment due to safety concerns does not seem to be supported by the evidence. (This study has been registered in ClinicalTrials.gov under identifier NCT04274101.).