Description
Fenbendazole(43210-67-9) is a benzimidazole anthelmintic.
1 It is active against
Giardia in vitro (IC
50 = 0.3 μM). Fenbendazole (20 mg/kg) prevents infiltration of parasites into the brain in a rabbit model of
E. cuniculi infection.
2 Fenbendazole also activates HIF-1α and prevents oxidative stress-induced death in primary neurons
in vitro.
3
Originator
Panacur,Hoechst,W. Germany,1980
Definition
ChEBI: A member of the class of benzimidazoles that is 1H-benzimidazole which is substituted at positons 2 and 5 by (methoxycarbonyl)amino and phenylsulfanediyl groups, respectively. A broad-spectrum anthelmintic, it is used, particularly in v
terinary medicine, for the treatment of nematodal infections.
Manufacturing Process
20.9 g of S-methyl-thiourea were dissolved in 27 ml of water with 13.5 ml of
chloroformic acid methyl ester. Then, 45.7 ml of 25% sodium hydroxide
solution were added dropwise, while stirring, at a temperature of 5°C to 10°C.
After having stirred for 20 minutes, the reaction mixture was combined with 27 ml of glacial acetic acid, 100 ml of water and 29 g of 3,4-diaminodiphenyl-
thioether. Stirring was continued for 90 minutes at a temperature of
85°C, during which time methyl-mercaptan was separated. After having
allowed the whole to cool and stand overnight, the 5-phenylmercaptobenzimidazole-
2-methyl-carbamate that had formed was filtered off with
suction. After recrystallization from a mixture of glacial acetic acid and
methanol, 14 g of 4-phenylmercapto-benzimidazole-2-methyl-carbamate
melting at 233°C were obtained.
Brand name
Panacur (Hoechst-Roussel).
Therapeutic Function
Anthelmintic
General Description
Fenbendazole is a thio substituted benzimidazole, which belongs to the group of anthelmintics. It can be widely used in veterinary medicine particularly, in the treatment of helminth infections.
Side effects
According to the results of toxicological studies, fenbendazole appears to be a safe drug, but up to 5% of people may experience stomach pain or diarrhea if taken in large amounts without interruption. People with severe renal failure or liver failure have a reduced level of drug excretion, and since fenbendazole powder is metabolized mainly in the liver, long-term heavy use can cause an asymptomatic increase in liver enzymes.
Veterinary Drugs and Treatments
Fenbendazole(43210-67-9) is indicated (labeled) for the removal of the following
parasites in dogs: ascarids (Toxocara canis, T. leonina), Hookworms
(Ancylostoma caninum, Uncinaria stenocephala),
whipworms
(Trichuris vulpis), and tapeworms (Taenia pisiformis). It is not effective
against Dipylidium caninum. Fenbendazole has also been
used clinically to treat Capillaria aerophilia, Filaroides
hirthi, and
Paragonimus kellicotti infections in dogs.
Fenbendazole is indicated (labeled) for the removal of the following
parasites in cattle: Adult forms of: Haemonchus contortus,
Ostertagia ostertagi, Trichostrongylus axei, Bunostomum phlebotomum,
Nematodirus helvetianus, Cooperia spp., Trichostrongylus
colubriformis, Oesophagostomum radiatum,
and Dictyocaulus vivaparus.
It is also effective against most immature stages of the above
listed parasites. Although not approved, it has good activity against
Moniezia spp., and arrested 4th stage forms of Ostertagia ostertagi.
Fenbendazole is indicated (labeled) for the removal of the following
parasites in horses: large strongyles (S. edentatus, S. equinus,
S. vulgaris), small strongyles (Cyathostomum spp., Cylicocylus
spp., Cylicostephanus spp., Triodontophorus spp.), and pinworms
(Oxyuris equi).
Fenbendazole is indicated (labeled) for the removal of the following
parasites in swine: large roundworms
(Ascaris suum), lungworms
(Metastrongylus pair), nodular worms (Oesphagostomum dentatum,
O. quadrispinolatum), small stomach worms (Hyostrongylus rubidus),
whipworms (Trichuris suis), and kidney worms (Stephanurus
dentatus; both mature and immature).
Although not approved, fenbendazole has been used in cats,
sheep, goats, pet birds, and llamas.
See Dosage section for more information.
Mode of action
Fenbendazole is a benzimidazole antiparasitic drug that works at the sub-cellular level preventing cell division. Benzimidazoles bind to the β-tubulin, inhibiting the cell’s microtubule assembly responsible for intracellular transport and required for mitotic cellular division. In effect, it starves the parasite by causing intestinal cell disruption.
References
[1] Gao P, et al. Unexpected antitumorigenic effect of fenbendazole when combined with supplementary vitamins. Journal of the American Association for Laboratory Animal Science : JAALAS, 2008.
[2] Park D, et al. Anti-cancer effects of fenbendazole on 5-fluorouracil-resistant colorectal cancer cells. The Korean Journal of Physiology Pharmacology, 2022; 26: 377-387.[3] Shin Y, et al. Anticancer Evaluation of Methoxy Poly(Ethylene Glycol)-b-Poly(Caprolactone) Polymeric Micelles Encapsulating Fenbendazole and Rapamycin in Ovarian Cancer. International Journal of Nanomedicine, 2023; 2023: 2209—2223.
