Multiple-dose kinetics of the trypanosomicide benznidazole in man.

The multiple-dose kinetics of N-benzyl-2-nitro-1-imidazole acetamide (benznidazole, Radanil) has been studied in eight patients with Chagas disease. The plasma level maxima and minima of the unchanged drug were measured on the 10th, 15th, 20th and 25th day of the four-week treatment (steady-state equilibrium). The measured values agreed well with the calculated values (calculation based on the pharmacokinetic parameters of benznidazole found in a preliminary single-dose study with healthy volunteers and the elimination half-life of each patient determined at the end of the treatment). The results indicate that benznidazole is a drug well suited for repeat dose schedules as applied and recommended in Chagas disease. No undue rise or fall in the drug plasma level should occur under these circumstances.