Indian Journal of Small Ruminants (The)

To assess the hypothesis that hepatic microsomal oxidation inhibitor methimazole (MTH) could increase bioavailability of albendazole (ABZ), a study was undertaken to understand the pharmacokinetics and efficacy of ABZ in goats with and without co-adminstration of ABZ with MTH at 7.5 and 3.0 mg/kg body weight, respectively. Significant increased values (P<0.05) of time to reach concentration maximum (calculated), area under concentration-time curve (0-∞), elimination half-life (t1/2β) and total area under the first movement of plasma drug concentration time curve were observed for ABZ-SO (albendazole sulphoxide) in goats following coadministration of ABZ and MTH. Faecal egg count reduction and lower 95% confidence limit revealed resistance and susceptible for ABZ alone and co-administration of ABZ and MTH, respectively. The dominant nematode exhibiting resistance was Haemonchus spp. ED 50 for egg hatch was 0.196 indicating resistance to benzimidazole. The study suggested that coadministration of ABZ and MTH affects pharmacokinetic disposition of ABZ, which could possibly result in potentiation of anthelmintic activity of ABZ as observed through faecal egg count reduction test.