Nifurtimox

The activity on the epimastigote forms of T. cruzi was evaluated on cultures in a LIT medium supplemented with 10% heat-inactivated (FCS). The parasites in the logarithmic growth phase (8–10 × 10⁶ epimastigote/mL) were distributed in 96-well flat-bottom plates (90 µL of culture/well). Essential oils and compounds (1,8-cineole and camphor from Sigma-Aldrich Quimica SL, Madrid, Spain) were tested in triplicate at several concentrations (EOs at 800, 400, 200, and 100 µg/mL; compounds at 100, 10, and 1 µg/mL) for 72 h. Nifurtimox (Bayer AG, Monheim am Rhein, Germany) was used as the positive control, and the parasite viability was analyzed by a modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay method [7 (link)]. Data were analyzed with Statgraphics statistical analysis software (Centurion XVIII, Statgraphics Technologies, Inc., The Plains, VA, USA) using one-way analysis of variance (ANOVA) and least significant difference (LSD) test (p < 0.05) analyses.

Nifurtimox used in this study was a kind gift provided by Bayer, Argentina. Fexinidazole was synthesized in-house as previously described.^{9 (link)}

Nifurtimox (120-mg tablets; Bayer) was prescribed in doses of 10 to 15 mg/kg per day divided into two or three daily doses for 60 to 90 days for infants and children, and 8 to 10 mg/kg for 30 days for adults, according to national guidelines. Enrollment of children started in January 1980 and for adults in July 2008. Treatment was considered complete when patients took the medication for at least 60 days for children and adolescents and 30 days for adults. Safety/tolerability of NF and adverse drug reaction (ADR) profiles, in this population, were evaluated and described by our group in a previous study (4 (link)).