Pharmacodynamic properties
ATC Vet Code: QP52AC13
Fenbendazole is an anthelmintic belonging to the benzimidazole carbamates group. It acts by interfering with the energy metabolism of the nematode. The anthelmintic efficacy is based on inhibition of the polymerisation of tubulin to microtubuli. The anthelmintic affects both adult and immature stages of gastro-intestinal and respiratory nematodes.
Pharmacokinetic properties
Fenbendazole is only partly absorbed after oral administration and is then metabolised in the liver.
The half-life of fenbendazole in serum after oral application of the recommended dose in cattle is 10-18 hours and in sheep 21-33 hours. Fenbendazole and its metabolites are distributed throughout the body and high concentrations can be found in the liver. The elimination of fenbendazole and its metabolites occurs primarily via the faeces (>90%) and to a small extent in the urine and milk. Fenbendazole is metabolised to its sulfoxide then to sulfone and amines.