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.

Fenbendazole
Clinical data
AHFS/Drugs.comInternational Drug Names
License data
ATC code
Identifiers
  • Methyl N-(6-phenylsulfanyl-1H-benzoimidazol-2-yl)carbamate
CAS Number
PubChem CID
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ECHA InfoCard100.051.024 Edit this at Wikidata
Chemical and physical data
FormulaC15H13N3O2S
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
  • Key:HDDSHPAODJUKPD-UHFFFAOYSA-N checkY
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Mechanism of Action

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Fenbendazole works by binding to tubulin, a protein that is part of the microtubules in the cells of parasites. This binding disrupts the microtubules' formation and function, leading to the parasites' inability to absorb nutrients, resulting in their eventual death. This mode of action makes fenbendazole effective against both adult and larval stages of many parasitic worms.[1][2]

Uses in Veterinary Medicine

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Dogs and Cats

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Fenbendazole is commonly used to treat intestinal parasites, including roundworms, hookworms, whipworms, and certain tapeworms. It is often administered as part of a broader deworming protocol. [3]

Horses

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In equine medicine, fenbendazole is used to control strongyles, pinworms, and ascarids. It is available in paste form for easy administration.[4]

Cattle and Goats

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Fenbendazole is effective against lungworms, stomach worms, and intestinal worms in ruminants. It is administered through feed, drenching, or bolus form.[5]

Drug interactions

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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.[6] Abortions in domestic ruminants have been associated with concurrent use of anti-trematode therapeutic agents.[7]

Dosage and Administration

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The appropriate dosage of the medication fenbendazole depends on the specific animal species being treated as well as the particular formulation or preparation of the fenbendazole product being used. To ensure the correct dosage considering the animal species being treated with its weight, using a dosage calculator like the Fenbendazole Paraclear Defense Dosage Calculator would be recommended.[8][9]

Toxicity

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Fenbendazole is poorly absorbed from the gastrointestinal tract in most species. The LD50 in laboratory animals exceeds 10 g/kg when administered orally.[6]

Metabolism

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Fenbendazole is metabolized in the liver to oxfendazole, which is anthelmintic too; oxfendazole partially gets reduced back to fenbendazole in the liver and rumen.[10][11] Also, fenbendazole itself is an active metabolite of another anthelmintic drug, febantel.[12]

Safety and Precautions

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Fenbendazole is generally safe when used as directed. However, it is important to follow veterinary guidelines and dosage instructions to avoid potential side effects. Some animals may experience mild gastrointestinal upset. It is not recommended for use in pregnant animals without veterinary advice.[13]

See also

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References

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  1. ^ Duan Q, Liu Y, Rockwell S (February 2013). "Fenbendazole as a potential anticancer drug". Anticancer Research. 33 (2): 355–362. PMC 3580766. PMID 23393324.
  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. doi:10.1038/s41598-018-30158-6. PMC 6085345. PMID 30093705.
  3. ^ "Fenbendazole (Panacur®, Safe-guard®) for Dogs and Cats". www.petmd.com. Retrieved 2024-07-01.
  4. ^ "What Is Fenbendazole and Is FenCare Right for My Horse? | Farnam". www.farnam.com. Retrieved 2024-07-01.
  5. ^ "Fenbendazole" (PDF).
  6. ^ a b Plumb DC (2005). Plumb's veterinary drug handbook (Fifth ed.). Stockholm, Wis.: PhrmaVet. ISBN 978-0-8138-0518-4.
  7. ^ Sarangi LN, Tharani N, Polapally S, Rana SK, Thodangala N, Bahekar VS, et al. (March 2021). "Infectious bovine abortions: observations from an organized dairy herd". Brazilian Journal of Microbiology. 52 (1): 439–448. doi:10.1007/s42770-020-00414-x. PMC 7966683. PMID 33415719.
  8. ^ "Fenbendazole (safe-Guard) dosing calculator". UK Aquatic Plant Society. 2023-04-10. Retrieved 2024-07-01.
  9. ^ "Fenbendazole (ParaClear Defense) Dosage Calculator 10% Solution". Retrieved 1 July 2024.
  10. ^ 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.
  11. ^ 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.
  12. ^ 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.
  13. ^ "Prescription Label" (PDF). Retrieved 1 July 2024.