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Clinical data
AHFS/Drugs.comInternational Drug Names
License data
ATC code
  • Methyl N-(6-phenylsulfanyl-1H-benzoimidazol-2-yl)carbamate
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.051.024 Edit this at Wikidata
Chemical and physical data
Molar mass299.35 g·mol−1
3D model (JSmol)
  • COC(=O)Nc3nc2ccc(Sc1ccccc1)cc2[nH]3
  • InChI=1S/C15H13N3O2S/c1-20-15(19)18-14-16-12-8-7-11(9-13(12)17-14)21-10-5-3-2-4-6-10/h2-9H,1H3,(H2,16,17,18,19) checkY
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Fenbendazole is a broad spectrum benzimidazole anthelmintic used against gastrointestinal parasites including: giardia, roundworms, hookworms, whipworms, the tapeworm genus Taenia (but not effective against Dipylidium caninum, a common dog tapeworm), pinworms, aelurostrongylus, paragonimiasis, strongyles, and strongyloides that can be administered to sheep, cattle, horses, fish, dogs, cats, rabbits, most reptiles, freshwater shrimp tanks as planaria and hydra treatments, as well as seals.

Drug interactions[edit]

Drug interactions may occur if salicylanilides such as dibromsalan and niclosamide are co-administered. Abortions in cattle and death in sheep have been reported after using these medications together.[1] Abortions in domestic ruminants have been associated with concurrent use of anti-trematode therapeutic agents.[citation needed]


Fenbendazole is poorly absorbed from the gastrointestinal tract in most species. The LD50 in laboratory animals exceeds 10 g/kg when administered orally.[1] Given its low toxicity and high tolerability among different species, the possibility of repurposing it as a drug to treat cancer in humans has been proposed.[2]


Fenbendazole is metabolized in the liver to oxfendazole, which is anthelmintic too; oxfendazole partially gets reduced back to fenbendazole in the liver and rumen.[3][4] Also, fenbendazole itself is an active metabolite of another anthelmintic drug, febantel.[5]

See also[edit]


  1. ^ a b Plumb DC (2005). Plumb's veterinary drug handbook (Fifth ed.). Stockholm, Wis.: PhrmaVet. ISBN 978-0-8138-0518-4.
  2. ^ Dogra N, Kumar A, Mukhopadhyay T (August 2018). "Fenbendazole acts as a moderate microtubule destabilizing agent and causes cancer cell death by modulating multiple cellular pathways". Scientific Reports. 8 (1): 11926. Bibcode:2018NatSR...811926D. doi:10.1038/s41598-018-30158-6. PMC 6085345. PMID 30093705. Fenbendazole is known to have a high safety margin and most species tolerate it very well. It has very low degree of toxicity and high degree of safety in experimental animals. In this study, we show that fenbendazole (FZ) exhibits a moderate microtubule depolymerizing activity towards human cancer cells, but possesses a potent antitumor effect as evident from in vitro and in vivo experiments.
  3. ^ Junquera P (2015-07-26). "Fenbendazole, Anthelmintic for Veterinary Use on Cattle, Sheep, Goats, Pig, Poultry, Horses, Dogs and Cats Against Roundworms and Tapeworms". PARASITIPEDIA. Retrieved 2015-09-08.
  4. ^ Junquera P (2015-07-26). "Oxfendazole, Anthelmintic for Veterinary Use on Cattle, Sheep, Goats, Horses, Dogs and Cats Against Roundworms and Tapeworms". PARASITIPEDIA. Retrieved 2015-09-08.
  5. ^ Junquera P (2015-07-26). "Febantel for Veterinary Use on Dogs, Cats, Cattle, Sheep, Goats, Pig and Poultry Against Roundworms and Tapeworms". PARASITIPEDIA. Retrieved 2015-09-08.