Fenbendazole (methyl N-(6-phenylsulfanyl-1H-benzimidazol-2-yl) carbamate) is a broad-spectrum benzimidazole anthelmintic that has been shown to be effective in the treatment of various intestinal helminth parasites and nematodes. It is also used in horses to treat cyathostomins, an important cause of colic.
The drug blocks the energy metabolism of parasites, preventing them from functioning and leading to their death. It is available in the United States by prescription only, and can be obtained from veterinary pharmacies or veterinary compounding companies. It is a commonly prescribed medication for gastrointestinal parasites in dogs and cats, and it is effective against the lungworm genus Taenia, pinworms, aelurostrongylus, parvovirulent canine enteric coronavirus, whipworms, and other tapeworms.
In addition to treating parasites, fenbendazole has demonstrated cytotoxic effects in cell culture. A 24-h incubation with high concentrations of the drug significantly reduced the clonogenicity and viability of cells of EMT6.
Veterinarians may prescribe this medication for other purposes, including destroying tumors, when the diagnosis is known or suspected. These uses are considered ‘off label’ or ‘extra label’ use, and must be prescribed by a licensed veterinarian. Fenbendazole can be given as oral granules or liquid suspension, and should be administered according to the dosage and directions on the veterinary medication label. It is often recommended to give the medication with food to reduce gastrointestinal upset. Some animals may react to fenbendazole by vomiting or having diarrhea, due to substances released by dying parasites. These reactions are not dangerous and should subside as the medication kills parasites. fenbendazole capsules