FENBENDAZOLE

Details

Stereochemistry	ACHIRAL
Molecular Formula	C15H13N3O2S
Molecular Weight	299.348
Optical Activity	NONE
Defined Stereocenters	0 / 0
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

COC(=O)NC1=NC2=C(N1)C=C(SC3=CC=CC=C3)C=C2

InChI

InChIKey=HDDSHPAODJUKPD-UHFFFAOYSA-N

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)

HIDE SMILES / InChI

Molecular Formula	C15H13N3O2S
Molecular Weight	299.348
Charge	0
Count

Stereochemistry	ACHIRAL
Additional Stereochemistry	No
Defined Stereocenters	0 / 0
E/Z Centers	0
Optical Activity	NONE

Description
Sources: http://www.fda.gov/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/ucm111175.htm
Curator's Comment: description was created based on several sources, including http://www.ema.europa.eu/docs/en_GB/document_library/Maximum_Residue_Limits_-_Report/2010/07/WC500094856.pdf http://www.inchem.org/documents/jecfa/jecmono/v29je04.htm http://www.ncbi.nlm.nih.gov/pubmed/15500920 http://www.ncbi.nlm.nih.gov/pubmed/3066771 http://docserver.ingentaconnect.com/deliver/connect/aalas/15596109/v46n6/s1.pdf?expires=1470315455&id=88320993&titleid=72010024&accname=Guest+User&checksum=A06372D2AC3E29195986E87F1731EB90

Fenbendazole (FBZ) is a broad-spectrum benzimidazole antiparasitic drug currently approved for use in numerous animal species, including rodents. Although nematodes, and in particular pinworms, are the main endoparasites of concern in laboratory rodents, FBZ also is indicated for use in other animal species against a wide spectrum of nematodes, tapeworms, flukes, and protozoa (Giardia duodenalis, Encephalitozoon intestinalis). The molecular mode of fenbendazole action consists in binding of beta-tubulin monomer prior to dimerisation with alfa-tubulin which blocks subsequent microtubule formation. These microtubules are important organelles involved in the motility, the division and the secretion processes of cells in all living organisms. In the worms the blocking of microtubules perturbs the uptake of glucose, which eventually empties the glycogen reserves. This blocks the whole energy management mechanism of the worms that are paralyzed and die or are expelled. FBZ have a greater binding to nematode as compared to mammalian tubulin at 37°C. The oral LD50 of p-OH fenbendazole was >10 000 mg/kg b.w. in mice and rats.

CNS Activity

Originator

Approval Year

Targets

Primary Target	Pharmacology	Condition	Potency
Tubulin beta chain 8 Target ID: Q9GSR5 Gene ID: NA Gene Symbol: TUB2 Target Organism: Encephalitozoon intestinalis (Microsporidian parasite) Sources: http://www.ncbi.nlm.nih.gov/pubmed/15500920	Inhibitor 8504		13.6 nM [Kd]

Conditions

Condition	Modality	Targets	Highest Phase	Product
Gastrointestinal parasitic disease 1 Sources: http://www.fda.gov/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/ucm111169.htm	Curative		Approved 8583	Panacur Approved Use I. GENERAL INFORMATION NADA 120-648 Sponsor: Hoechst Roussel Vet 30 Independence Blvd. P.O. Box 4915 Warren, NJ 07059 Generic Name: fenbendazole Trade Name: Panacur ® and Safe-Guard® Marketing Status: Over the Counter (OTC) Effect of Supplement: For treatment of encysted.mucosal cyathostome (small strongyle) larvae including hypobiotic early third stage, late third stage and fourth stage larvae at 10 mg/kg/day for 5 consecutive days. II. INDICATIONS FOR USE Fenbendazole Paste 10% is indicated for the control of large strongyles (Strongylus edentatus, S. equinus, S. vulgaris), small strongyles (cyathostomes) including encysted early 3rd stage (hypobiotic), late third stage and fourth stage mucosal cyathostome larvae, pinworms (Oxyuris equi), ascarids (Parascaris equorum), and arteritis caused by 4th stage larvae of Strongylus vulgaris in horses. Fenbendazole Paste 10% is approved for use concomitantly with an approved form of trichlorfon. Trichlorfon is approved for the treatment of stomach bots (Gasterophilus spp.) in horses. Refer to the manufacturer’s label for directions for use and cautions for trichlorfon. III. DOSAGE A. DOSAGE FORM: paste B. ROUTE OF ADMINISTRATION: oral C. RECOMMENDED DOSAGES: Fenbendazole Paste 10% is administered orally at a rate of 2.3 mg/lb (5 mg/kg) for the control of large strongyles, small strongyles (cyathostomes), and pinworms. For foals and weanlings (less than 18 months of age) where ascarids are a common problem, the recommended dose is 4.6 mg/lb (10 mg/kg). For control of encysted early third stage (hypobiotic), late third stage and fourth stage mucosal cyathostome larvae and 4th stage larvae of Strongylus vulgaris, the recommended dose is 4.6 mg/lb (10 mg/kg) daily for 5 consecutive days. Launch Date 1985
Cancer 609 Sources: http://www.ncbi.nlm.nih.gov/pubmed/23393324	Primary		Basic research	Unknown Approved Use Unknown

Doses

Dose	Population	Adverse events
1.5 g single, oral Highest studied dose Dose: 1.5 g Route: oral Route: single Dose: 1.5 g Sources: https://pubmed.ncbi.nlm.nih.gov/779682/	unhealthy, CHILD Health Status: unhealthy Age Group: CHILD Sex: M+F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/779682/	Other AEs: Vomiting... Other AEs: Vomiting (5.9%) Sources: https://pubmed.ncbi.nlm.nih.gov/779682/

AEs

AE	Significance	Dose	Population
Vomiting	5.9%	1.5 g single, oral Highest studied dose Dose: 1.5 g Route: oral Route: single Dose: 1.5 g Sources: https://pubmed.ncbi.nlm.nih.gov/779682/	unhealthy, CHILD Health Status: unhealthy Age Group: CHILD Sex: M+F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/779682/

PubMed

Title	Date	PubMed
Modulation of porcine biotransformation enzymes by anthelmintic therapy with fenbendazole and flubendazole.	2006-06	16125742
Immunomodulatory effect of various anti-parasitics: a review.	2006-03	16332285
Further characterisation of a triple resistant field isolate of Teladorsagia from a Scottish lowland sheep farm.	2005-12-10	16168563
Comparing different formulae to test for gastrointestinal nematode resistance to benzimidazoles in smallholder goat farms in Mexico.	2005-12-10	16111815
Evaluation of silymarin in the treatment on asymptomatic Giardia infections in dogs.	2005-12	16151741
Aelurostrongylus abstrusus (cat lungworm) infection in five cats from Italy.	2005-11-25	16076529
Verminous pneumonia due to Filaroides hirthi in a Scottish terrier in Spain.	2005-11-05	16272546
Field evaluation of the efficacy of fenbendazole in captive wild ruminants.	2005-11-05	16272545
Thrombo-ischaemic pinnal necrosis associated with fenbendazole treatment in a dog.	2005-05	15909448
Changes to oxfendazole chiral kinetics and anthelmintic efficacy induced by piperonyl butoxide in horses.	2005-05	15892236
Transport of anthelmintic benzimidazole drugs by breast cancer resistance protein (BCRP/ABCG2).	2005-05	15703302
Individual intake and antiparasitic efficacy of free choice mineral containing fenbendazole for grazing steers.	2005-04-20	15817200
Relationships among fecal lungworm loads, fecal glucocorticoid metabolites, and lamb recruitment in free-ranging Rocky Mountain bighorn sheep.	2005-04	16107677
Microbial inhibition by pharmaceutical antibiotics in different soils--dose-response relations determined with the iron(III) reduction test.	2005-04	15839561
The lack of behavioral effects of fenbendazole: a medication for pinworm infection.	2005-03	15773771
Identification of strongyle eggs from anthelmintic-treated horses using a PCR-ELISA based on intergenic DNA sequences.	2005-03	15682337
Intracranial haemorrhage associated with Angiostrongylus vasorum infection in three dogs.	2005-02	15736817
Cerebral and conjunctival haemorrhages associated with von Willebrand factor deficiency and canine angiostrongylosis.	2005-02	15736813
Eradication of Syphacia muris from food-restricted rats without environmental decontamination.	2005-01	15697194
Clinical, cytological and molecular evidence of Mesocestoides sp. infection in a dog from Italy.	2004-12	15610488
Characterisation of benzimidazole binding with recombinant tubulin from Giardia duodenalis, Encephalitozoon intestinalis, and Cryptosporidium parvum.	2004-11	15500920
Effect of the antiparasitic drugs fenbendazole and ivermectin on the soil nematode Pristionchus maupasi.	2004-09-20	15350664
Prevalence of anthelmintic resistant cyathostomes on horse farms.	2004-09-15	15485051
Effect of repeated benzimidazole treatments with increasing dosages on the phenotype of resistance and the beta-tubulin codon 200 genotype distribution in a benzimidazole-resistant cyathostomin population.	2004-09-02	15325046
Characterisation of two triple resistant field isolates of Teladorsagia from Scottish lowland sheep farms.	2004-09-02	15325045
Angiostrongylus vasorum infection in 23 dogs (1999-2002).	2004-09	15460201
Variability in the resistance of the Nigerian West African Dwarf goat to abbreviated escalating trickle and challenge infections with Haemonchus contortus.	2004-06-10	15158556
Bone marrow hypoplasia associated with fenbendazole administration in a dog.	2004-05-08	15131104
Comparative hepatic and extrahepatic enantioselective sulfoxidation of albendazole and fenbendazole in sheep and cattle.	2004-05	15100176
Intestinal DNases of 36 and 38.5kDa from the parasitic nematode Haemonchus contortus have non-classic DNase characteristics and produce DNA fragments with 3'-hydroxyls.	2004-04-08	15582511
Radiographic findings in 16 dogs infected with Angiostrongylus vasorum.	2004-04-03	15119894
Reversible pulmonary hypertension presenting simultaneously with an atrial septal defect and angiostrongylosis in a dog.	2004-04	15116890
The effects of fenbendazole, flubendazole and mebendazole on activities of hepatic cytochromes P450 in pig.	2004-04	15096105
Benzimidazole drugs and modulation of biotransformation enzymes.	2004-04	14672851
Long-term results of dietary fenbendazole to eradicate Syphacia muris from rat colonies.	2004-03	15053507
Prevalence of benzimidazole resistance on horse farms in Germany.	2004-01-10	14758828
Comparative assessment of the access of albendazole, fenbendazole and triclabendazole to Fasciola hepatica: effect of bile in the incubation medium.	2004-01	15002906
Evaluation of copper supplementation to control Haemonchus contortus infections of sheep in Sweden.	2004	15663075
Quantitative chromatographic determination of several benzimidazole anthelmintic molecules in parasite material.	2003-12-05	14630366
Multiresistant nematodes on a Devon farm.	2003-11-08	14640331
Non-classic characteristics define prominent DNase activities from the intestine and other tissues of Haemonchus contortus.	2003-10-14	14552860
Investigations on the influence of helminth parasites on vaccination of chickens against Newcastle disease virus under village conditions.	2003-10	14620586
Field test data on small strongyles in evaluation of activity of fenbendazole given once a day for 5 consecutive days to thoroughbred yearlings on two farms in Kentucky in 2002 and 2003.	2003-10	14574561
Anthelmintic resistance of nematodes in communally grazed goats in a semi-arid area of South Africa.	2003-09	15029952
Expulsion of small strongyle nematodes (cyathostomin spp) following deworming of horses on a stud farm in Sweden.	2003-08-14	12944042
Evaluation of fenbendazole for treatment of Giardia infection in cats concurrently infected with Cryptosporidium parvum.	2003-08	12926597
Synergistic effects of pyrantel and the febantel metabolite fenbendazole on adult Toxocara canis.	2003-07	12928887
Anthelmintic treatment in horses: the extra-label use of products and the danger of under-dosing.	2003-06	12967052
Effect of feeding urea-molasses blocks with incorporated fenbendazole on grazing dairy heifers naturally infected with gastrointestinal nematodes.	2003-06	12967051
Disintegration of dung pats from cattle treated with the ivermectin anthelmintic bolus, or the biocontrol agent Duddingtonia flagrans.	2003	15074630

Patents

Sample Use Guides

In Vivo Use Guide

300 mg with breakfas 600 mg 12 hours after last meal

Route of Administration: Oral

In Vitro Use Guide

A concentration of Fenbendazole required to inhibit larval development activity of Haemonchus contortus by 50% (LD50) was 0.019 uM.

Substance Class	Chemical Created by `admin` on `Wed Apr 02 08:46:56 GMT 2025` Edited by `admin` on `Wed Apr 02 08:46:56 GMT 2025`
Record UNII	621BVT9M36
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

FENBENDAZOLE

Official Name

English

FENBENDAZOLE FOR VETERINARY USE

Preferred Name

English

HOE-881Y

Code

English

FENBENDAZOLE [USAN]

Common Name

English

FENBENDAZOLE [MI]

Common Name

English

Fenbendazole [WHO-DD]

Common Name

English

FENBENDAZOLE FOR VETERINARY USE [EP IMPURITY]

Common Name

English

FENBENDAZOLE [USP-RS]

Common Name

English

FENBENDAZOLE [EMA EPAR VETERINARY]

Common Name

English

OXFENDAZOLE IMPURITY, FENBENDAZOLE- [USP IMPURITY]

Common Name

English

HOE 881V

Code

English

HOE-881V

Code

English

PANACUR

Brand Name

English

CARBAMIC ACID, (5-(PHENYLTHIO)-1H-BENZIMIDAZOL-2-YL)-, METHYL ESTER

Common Name

English

fenbendazole [INN]

Common Name

English

PANACUR AQUASOL

Brand Name

English

NSC-757824

Code

English

FENBENDAZOLE [USP MONOGRAPH]

Common Name

English

FENBENDAZOLE [GREEN BOOK]

Common Name

English

FENBENDAZOLE FOR VETERINARY USE [EP MONOGRAPH]

Common Name

English

OXFENDAZOLE FOR VETERINARY USE IMPURITY A [EP IMPURITY]

Common Name

English

Methyl 5-(phenylthio)-2-benzimidazolecarbamate

Common Name

English

Classification Tree Code System Code

CFR

21 CFR 520.905C