Brand: FEN-IVERQUANTEL Paste
CHEMICAL CLASS of the active ingredient(s):
PARASITES CONTROLLED* (spectrum of activity)
* Country-specific differences may apply: read the product label.
- Large strongyles: Strongylus vulgaris (adults and arterial stages); Strongylus edentatus (adults and visceral stages); Strongylus equinus (adults)Triodontophorus brevicauda (adults), Triodontophorus spp
- Small strongyles: Adult and immature (fourth stage larvae) small strongyles or cyathostomes: Cyathostomum spp, Cylicocyclus spp, Cylicostephanus spp, Cylicodontophorus spp, Gyalocephalus spp, etc.
Pinworms (adults and larval stages): Oxyuris equi
- Ascarids (adults and larval stages): Parascaris equorum
- Stomach worms:Trichostrongylus axei (adults), Habronema muscae
- Intestinal threadworms: Strongyloides westeri
- Lungworms (adult & immature): Dictyocaulus arnfieldi
- Stomach bots: Oral and gastric stages of Gasterophilus spp, horse bot flies
Adult Tapeworms: Anoplocephala perfoliata
*Can be slightly different in some countries: read the product label!
- 1 syringe division of paste per 100 kg bodyweight (one 30 mL syringe will treat a 600 kg horse): equivalent to 0.2 mg ivermectin per kg bodyweight (= 200 mcg/kg), 10 mg fenbendazole per kg bodyweight and 2.5 mg praziquantel per kg bodyweight.
Read the product label for further details on dosing
- LD50 (acute oral) in rats: >5000 mg/kg (estimate calculated according to the WHO based on the ivermectin LD50)
- Estimated hazard class according to the WHO: not applicable for veterinary medicines
Withholding periods (=withdrawal times) for meat (country-specific differences may apply: read the product label)
- MEAT & OFFAL: New Zealand: 28 days
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
- Small strongyles (cyathostomes). Tolerance of small strongyles to macrocyclic lactones (e.g. ivermectin, moxidectin), manifested as a low but significant worm egg output after treatment (determined after fecal egg counts) is not yet widespread, but has been already reported in Europe (e.g. in the UK, Germany, Italy), the USA, and Brazil. Resistance of small strongyles to benzimidazoles (incl. fenbendazole) is widespread and frequent in Australia, USA, UK and Europe, Argentina, Chile, Uruguay, etc.
- Parascaris equorum: Cases of resistance to macrocyclic lactones (e.g. ivermectin, moxidectin) and to benzimidazoles have been reported as well (e.g. in the USA and Australia).
This means that if this product does not achieve the expected efficacy against the mentioned parasites, it may be due to resistance and not to incorrect use, which is usually the most frequent cause of product failure.
It is generally accepted that the use of mixtures of active ingredients with different modes of action against a given parasite can delay the appearance of resistance. But only if the concerned parasites are susceptible to all the actives in the mixture. If not, the mixture is likely to promote multi-resistant parasites, because the selection pressure against all actives remains in place. Mixtures such as this one may provide peace-of mind to those users that do not know the resistance status of worms in their property: at least one of the actives will work... This may be the case for a while. But the risk that some worm species become resistant to all components after a few years using the same or comparable mixtures is considerable. If it is not too late, a better alternative is to determine the resistance status in the property and to rotate among products (not mixtures) against which the worms have not yet developed resistance, stopping the use of those chemical classes that have already shown resistance problems.
- Imidazothiazoles, mainly levamisole. Not approved for use in horses in many countries.
- Tetrahydropyrimidines, mainly pyrantel (limited spectrum of activity), but resistance cases have also been reported (e.g. Australia, USA, Brazil, Japan).
These alternative products may not be available in all countries, or may not be available as oral pastes or gels.
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 product is marketed: New Zealand
GENERIC BRANDS available? YES, but maybe not with the same composition.
Click here to learn more about GENERIC vs. ORIGINAL drugs.
FEN-IVERQUANTEL oral paste for horses is a classic horse wormer from CALEDONIAN with ivermectin, fenbendazole and praziquantel. Ivermectin is effective against roundworms and bots, fenbendazole against roundworms and tapeworms, praziquantel against tapeworms.
Ivermectin is a broad spectrum parasiticide with efficacy against internal parasites (mainly roundworms) and against external parasites as well (mainly mites, lice, grubs, etc). This is why it is called an endectocide (controls endoparasites and ectoparasites). Ivermectin was the first macrocyclic lactone discovered and introduced in the 1980s by MS&D AgVet (now MERIAL). It is the parasiticide for livestock and pets most widely used worldwide, with probably thousands of generic brands. Ivermectin is probably the best veterinary parasiticide ever developed, highly effective against roundworms and, depending on the delivery form and formulation, also against numerous external parasites (ticks, flies, lice, mites, etc.). As all macrocyclic lactones, ivermectin used alone is ineffective against tapeworms and flukes, regardless of the delivery form. It is massively used in livestock and horses, less in pets. Ist is also used as a human medicine, and against agricultural and household pests.
Ivermectin and other macrocyclic lactones have about two weeks residual effect on horses because they are stored in body fat and progressively released. This, together with the time that worms need to develop inside the horse after infection (pre-patent period) allows to space the treatment intervals to 10 to 12 weeks in year-round control programs in many regions. For other active ingredients that have no residual effect such as fenbendazole, mebendazole, or pyrantel the treatment interval is usually 4 to 6 weeks.
Whereas in ruminants ivermectin administered at 200 mcg/kg controls a series of external parasites as well (mites, lice, etc.), such an indication is not approved in most countries in horses: external parasites have to be controlled with ectoparasiticides (e.g. pour-ons, sprays, etc.).
Fenbendazole is a veteran benzimidazole introduced in the 1970s (by HOECHST → INTERVET → MSD ANIMAL HEALTH) that is abundantly used in livestock and horses, moderately in pets. It is a broad-spectrum anthelmintic effective against roundworms in the gut and the lungs, but not against those in the skin. It is also ineffective against gastric bots (Gasterophilus spp) or whatever external parasites. At the recommended dose it is also ineffective against horse tapeworms (Anoplocephala spp).
Praziquantel is a veteran anthelmintic introduced in the 1970s (by BAYER). It is highly effective against tapeworms (in horses mainly Anoplocephala spp) but has no efficacy whatsoever against roundworms. It is the anthelmintic most vastly used against tapeworms in horses and pets, used in hundreds of brands. It is hardly used in livestock. It is not used in agriculture.
Many horse owners complain about the price of the oral pastes & gels for horses (with ivermectin or other macrocyclic lactones), compared with the much cheaper injectables for livestock with the same active ingredients, used at the same dose (200 mcg/kg). This is why off-label use of livestock ivermectin injectables in horses is very common worldwide, particularly in working horses of cattle and sheep ranches. The reason why injectables are mostly not approved for use on horses is apparently that, shortly after introduction, it was noticed that horses were more prone to develop severe clostridial infections at the injection site (due to contamination of the needles) and other undesired side effects than cattle or sheep. In addition, the pharmacokinetic behavior of ivermectin on horses is different than in ruminants. For these reasons oral pastes were developed for horses that do not show such side effects. However, in numerous countries (e.g. in Latin America) some ivermectin injectables for livestock are also approved for use on horses.
For an overview and a list of the most used oral paste & gel brands click here.
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.