Benznidazole treatment safety: the Médecins Sans Frontières experience in a large cohort of Bolivian patients with Chagas' disease.

Background: Up to half of patients with Chagas' disease under benznidazole treatment present adverse drug reactions (ADRs) and up to one-third do not complete standard treatment. Objectives: To verify the incidence and possible factors associated with the suspension of benznidazole treatment in a large cohort of patients. Methods: We included 2075 patients treated with benznidazole during the projects managed by the medical humanitarian organization Doctors Without Borders (Medecins Sans Frontieres) in Bolivia from 2009 to 2013. Benznidazole treatment was provided two or three times per day for similar to 60 days at 5-7.5 mg/kg/day. A multiple logistic regression model was developed to evaluate the factors associated with permanent suspension of benznidazole treatment. Results: Permanent benznidazole treatment suspension occurred in 211 patients (10.2%) and the average time until permanent treatment suspension was 23 days. Multifactorial analysis revealed that female sex (adjusted OR=1.70), moderate ADRs (adjusted OR=10.57), mild ADRs (adjusted OR=1.69) and skin disorders (adjusted OR=4.18) were significantly associated with the permanent suspension of benznidazole treatment. Women with mild or moderate skin ADRs presented a probability of treatment interruption of 18.6% and 59.0%, respectively. Conclusions: Benznidazole treatment was safe and a large proportion of patients were able to complete a full course of benznidazole treatment under close treatment surveillance. Female sex, skin disorders and mild and moderate ADRs were independently associated with the permanent suspension of benznidazole treatment. In particular, women with moderate skin ADRs had the highest risk of benznidazole treatment interruption.