Brand: DURAFEND ™
DELIVERY FORM: pellets, «feed additives and medicated feeds» for oral administration.
ACTIVE INGREDIENT(S): fenbendazole 5 g/kg (=2.27 g/lb) (equivalent to 0.5%)
CHEMICAL CLASS of the active ingredient(s): benzimidazole
INDICATIONS: CATTLE (Beef & Dairy), HORSES, WILD ANIMALS
PARASITES CONTROLLED (spectrum of activity)*
- Roundworms: Lungworms: (Dictyocaulus viviparus). Stomach worms: Barberpole worms (Haemonchus contortus), brown stomach worms (Ostertagia ostertagi), small stomach worms (Trichostrongylus axei). Intestinal worms: Hookworms (Bunostomum phlebotomum), thread-necked intestinal worms (Nematodirus helvetianus), small intestinal worms (Cooperia punctata & Cooperia oncophora), Bankrupt worms (Trichostrongylus colubriformis), Nodular worms (Oesophagostomum radiatum).
- For the control of large strongyles (Strongylus edentatus, Strongylus equinus, Strongylus vulgaris, Triodontophorus spp.), small strongyles (Cyathostomum spp., Cylicocyclus spp., Cylicostephanus spp.), pinworms (Oxyuris equi), and ascarids (Parascaris equorum).
* Read the product label for parasites controlled in wild animals
* Country-specific differences may apply: read the product label.
- Cattle: 5 mg fenbendazole per kg body weight (=2.27 mg fenbendazole per pound of body weight) in a one (1) day treatment.
- for large strongyles, small strongyles and pinworms: 5 mg fenbendazole per kg body weight (=2.27 mg fenbendazole per pound of body weight) in a one (1) day treatment
- for ascarids: 10 mg fenbendazole per kg body weight (4.54 mg fenbendazole per pound) in a ONE (1) DAY treatment
Read the product label for specific detail on dosage.
- LD50 (acute oral) in rats: >10000 mg/kg (for the a.i.)
- LD50 (acute dermal) in rats: n.a.
Suspected poisoning? Read the article on fenbendazole safety in this site.
Withholding periods (=withdrawal times) in days for meat & milk (country-specific differences may apply: read the product label)
- Cattle: 13 days.
- Horses: Do not use in horses intended for human consumption
- Milk for human consumption:
- Cattle: NIL
WARNING !!!: Never use on humans, dogs or cats
You may be interested in the following articles in this site dealing with the general safety of veterinary products:
- Safety for humans
- Safety for domestic animals
- Safety for the environment
- Hazard classifications of pesticides
Risk of resistance? YES, resistance of gastrointestinal roundworms to all benzimidazoles (incl. fenbendazole) in ruminants is a very serious and increasing problem worldwide, particularly in sheep and goats, but also in cattle. The most affected worm species are:
- Sheep & goats: Haemonchus spp, Ostertagia spp /Teladorsagia spp, Trichostrongylus spp, Nematodirus spp, Chabertia ovina.
- Cattle: Cooperia spp, Haemonchus spp, Ostertagia spp, Trichostrongylus spp, Oesophagostomum spp.
- Small strongyles (cyathostomes). Resistance of small strongyles to benzimidazoles is widespread and frequent e.g. in the USA, UK and Europe, Argentina, Chile, Uruguay, etc.
- Parascaris equorum: Cases of tolerance to benzimidazoles have been also reported (e.g. in the USA).
This means that if this product does not achieve the expected efficacy against the mentioned parasites, it can be due to resistance and not to incorrect use, which is usually the most frequent cause of product failure.
Alternative chemical classes/active ingredients to prevent resistance of external parasites through product rotation:
- Macrocyclic lactones (e.g. abamectin, doramectin, eprinomectin, ivermectin, moxidectin, etc.). Resistance to macrocyclic lactones is also increasing and strengthening quickly in many countries.
- Levamisole. Resistance to levamisole has been reported in most countries, but is usually less strong and frequent than to benzimidazoles.
- Salicylanilides (e.g. closantel): only in some countries against certain gastrointestinal roundworm species. Resistance to closantel has been reported in some countries.
- Tetrahydropyrimidines (e.g. morantel, pyrantel): only against certain gastrointestinal roundworms in some countries. Resistance to morantel has been reported in some countries.
- Nitroxinil: only against a few gastrointestinal roundworms (e.g. Bunostomum spp, Haemonchus spp, Oesophagostomum spp). Not available in some countries.
These alternative products may not be available in all countries, or may not be effective against all the concerned parasites.
It is highly recommended to periodically check the resistance status of each property performing appropriate tests (e.g. fecal egg counts) under supervision of a veterinary doctor. Such tests are now routinely available for most producers in developed countries.
So far there are no reports on resistance of swine roundworms to benzimidazoles.
Learn more about resistance and how it develops.
Are the active ingredients of this product ORIGINAL* or GENERICS**?
*Meaning that they are still patent protected and generics are not yet available
**Meaning that they have lost patent protection and may be acquired from manufacturers of generic active ingredients other than the holder of the original patent.
COUNTRIES where this brand/product is marketed: USA.
GENERIC BRANDS available? Yes, in most countries. This product itself contains generic fenbendazole.
Click here to learn more about GENERIC vs. ORIGINAL drugs.
Click here for an overview on the most used antiparasitic feed additives and medicated feeds for livestock and horses.
DURAFEND is a medicated dewormer brand from DURVET for cattle, horses and wild animals containing generic fenbendazole.
Fenbendazole is a veteran anthelmintic introduced in the 1970s (by HOECHST, now MSD = MERCK ANIMAL HEALTH). Fenbendazole has a broad-spectrum of activity against roundworms (gastrointestinal and pulmonary) and, depending on the dose also against tapeworms, but is ineffective against flukes. Fenbendazole also kills eggs of roundworms (ovicidal activity). As all benzimidazoles, fenbendazole has no efficacy whatsoever against external parasites (ticks, flies, lice, mites, etc). Among the benzimidazoles fenbendazole is quite comparable with oxfendazole in terms of efficacy and safety. Fenbendazole is abundantly used worldwide in numberless generic brands for livestock, horses and pets.
As all benzimidazoles (as well as other anthelmintics such as levamisole, monepantel, and tetrahydropyrimidines), fenbendazole for oral administrartion has no residual effect, i.e. it kills the parasites shortly after administration, but as soon as medicated feeding is interrupted it does not significantly protect the animals against re-infestation by infective stages in their environment.
Both for livestock and pets fenbendazole is often used in combinations that broaden the spectrum of activity or try to overcome potential resistance. Typical mixtures for livestock include a flukicide (e.g. closantel, etc.) and/or a macrocyclic lactone, and/or levamisole, although such mixtures are not approved everywhere. For dogs and cats it is often combined with a taenicide (e.g. praziquantel).
Click here for general information on good practices for the prevention and control of gastrointestinal worms in livestock.
This article IS NOT A PRODUCT LABEL. It offers complementary information that may be useful to veterinary professionals and users that are not familiar with veterinary antiparasitics.
Information offered in this article has been extracted from publications issued by manufacturers, government agencies (e.g. EMEA, FDA, USDA, etc.) or in the scientific literature. No guarantee is given on its accuracy, integrity, sufficiency, actuality and opportunity, and any liability is denied. Read the site's DISCLAIMER.
In case of doubt contact the manufacturer or a veterinary professional.