Fenbendazole

EMA approved medicines: Veterinary medicine

FDA approved animal drugs -> Active ingredient

Pharmaceuticals -> UK Veterinary Medicines Directorate List

Pharmaceuticals -> Animal Drugs -> Approved in Taiwan

174.9 Ų [M-H]- [CCS Type: DT; Buffer gas: N2; Ionization: ESI-; Dataset: TOXCAST; Source Identifier: DTXSID0040672]

170.8 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

186.5 Ų [M+Na]+ [CCS Type: TW; Method: calibrated with Waters Major Mix]

169.8 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

This chemical does not meet GHS hazard criteria for 1.3% (2 of 157) of reports.

Warning

H361 (66.2%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

P203, P260, P273, P280, P318, P319, P391, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 157 reports by companies from 14 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

The side effects of fenbendazole therapy in humans have not been well described, but other benzimidazoles are associated with transient and asymptomatic elevations in serum aminotransferase levels in up to 50% of patients treated for more than a few weeks. These abnormalities rapidly improve with stopping therapy. Fenbendazole taken by patients without prescription for its purported antineoplastic activity has been associated with several instances of clinically apparent liver injury. The onset of injury has been within a few days to as long as a year after starting therapy or more rapidly with multiple courses of treatment. The pattern of serum enzyme elevations is typically hepatocellular or mixed. Allergic features (rash, fever, eosinophilia) may be present but are not prominent. Most cases have been mild to moderate in severity, and recovery is rapid once the drug is stopped. However, some cases have been severe and potentially life-threatening. Rapid recurrence with rechallenge has been reported with other benzimidazoles but with similar severity.

Fenbendazole has a high safety margin and low toxicity in animals. A study of fenbendazole administered to cattle found that it was well-tolerated, even when administered at six times the prescribed dose and three times the recommended duration. The lethal dose (LD50) in rodents is greater than 10 g/kg, which is 1,000 times the therapeutic level. Lifetime studies in rats indicated no maternal or reproductive toxicity and no carcinogenesis.

Fenbendazole (FBZ) is used to treat or prevent pinworm outbreaks in laboratory rodents. At therapeutic levels, FBZ does not alter the total content of cytochromes P450 but does induce certain hepatic cytochrome P450 isoforms known for bioactivating a number of procarcinogens. Lifetime studies in rats have shown that FBZ is not a carcinogen but that it may behave as a tumor promoter when given after certain initiators. FBZ treatment-associated myelosuppression has not been reported to occur in rodents.

P - Antiparasitic products, insecticides and repellents

QP - Antiparasitic products, insecticides and repellents

Due to its poor absorption by oral administration, fenbendazole is particularly effective for targeting intestinal parasites. It exerts its antiparasitic effects primarily in the anterior intestine by depolymerizing microtubules, inhibiting intestinal secretory vesicle transport. When fenbendazole binds to beta-tubulin in parasites, it causes microtubule destabilization and hinders tubulin polymerization. This destabilization disrupts cellular function, such as glucose uptake, and thus affects the energy management of parasites.

Fenbendazole is a benzimidazole anthelmintic agent commonly used to treat animal parasitic infections. In humans, other benzimidazoles, such as mebendazole and albendazole, are used as antiparasitic agents. Fenbendazole is not currently approved by the FDA or EMA and its pharmacokinetics and safety in humans are not well-documented.

Veterinary Drug -> ANTHELMINTHIC_AGENT -> JECFA Functional Classes

Veterinary Drug -> ANTHELMINTHIC_AGENT -> JECFA Functional Classes

Veterinary Drug -> ANTHELMINTHIC_AGENT -> JECFA Functional Classes

Veterinary Drug -> ANTHELMINTHIC_AGENT -> JECFA Functional Classes

Veterinary Drug -> ANTHELMINTHIC_AGENT -> JECFA Functional Classes

Pharmaceuticals -> Animal Drugs -> Approved in Taiwan