Disposition of fenbendazole in the rabbit.

The disposition of fenbendazole was studied in rabbits following either oral or intravenous administration. The major metabolites appearing in plasma were fenbendazole sulphoxide (oxfendazole) and fenbendazole sulphone. Calculation of the total urinary and faecal elimination of the drug and of its known metabolites showed that only 40 per cent of the dose was recovered after oral dosing; 29.7 per cent after an intravenous dose. The sulphoxide and sulphone were minor elimination products. The major excretory metabolite was p-hydroxyfenbendazole.