RESUMO
Chagas disease is a serious public health problem in Latin America and, due to migration, in other non-endemic regions. Benznidazole (BNZ) is first choice drug in pediatric therapeutics. However, little is known regarding its metabolism in humans. The aim of the study was to isolate and identify products of human BZN metabolism in urine samples obtained from a pediatric Chagas patient and a healthy adult volunteer both treated with BZN. Urine samples were collected after dose of BNZ. Urine was treated with β-glucuronidase followed by an extraction procedure under two different pH conditions and a HPLC/UV and MS/MS identification of BZN and its metabolites. BZN (m/z 260.09847) was identified in all urine extracts. Peaks from each extracted chromatograms were selected for MS and MS/MS identification. Three compounds structurally related to BZN were identified: BZN-Na+ (m/z 283.08009), N-amine-BZN (m/z 230.12307) and N-hydroxi-amine-BZN (m/z 246.11702). BNZ-Na+ was identified in all extracts, but N-amine-BZN and N-hydroxi-amine-BZN were only observed in those extracts treated with β-glucuronidase. This is the first experimental report showing elimination of BZN N-reduced metabolites in urine. As they were released after treatment with β-glucuronidase it can be suggested that glucuronization plays a role in BNZ metabolism and renal elimination.
RESUMO
Pharmacological treatment of Chagas disease with benznidazole (BNZ) is effective in children in all stages, but it is controversial in chronically infected adults. We report the pharmacokinetics and pharmacodynamics in six adult patients with Chagas disease treated with the new BNZ formulation (ABARAX®) in doses between 2.5-5.5 mg/Kg/day. All but one patient had plasmatic BNZ concentrations within the expected range. All patients finalised treatment with nondetectable Trypanosoma cruziquantitative polymerase chain reaction, which remained nondetectable at the six month follow-up. Our data suggests parasitological responses with the new BNZ and supports the hypothesis that treatment protocols with lower BNZ doses may be effective.