Brand: IVERMECTIN PASTE
FORMULATION: «oral paste» in pre-charged syringes
ACTIVE INGREDIENT(S): ivermectin: 1.87% (= 18.7 mg/mL)
CHEMICAL CLASS of the active ingredient(s): macrocyclic lactone
PARASITES CONTROLLED* (spectrum of activity)
* Country-specific differences may apply: read the product label.
- Large strongyles (adults) Strongylus vulgaris (also early forms in blood vessels); Strongylus edentatus (also tissue stages); Strongylus equinus; Triodontophorus spp; Craterostomum acuticaudatum (adults)
- Small strongyles: Adult and fourth stage larvae) als called cyathostomes: a group of about 40 different species that varies from country to country.
- Lungworms (adults and fourth-stage larvae): Dictyocaulus arnfieldi
- Pinworms (adults and fourth-stage larvae): Oxyuris equi
- Ascarids (adults and third- and fourth-stage larvae): Parascaris equorum
- Hairworms (adults):Trichostrongylus axei
- Large-mouth stomach worms (adults): Habronema muscae
- Dermatitis caused by Neck threadworms microfilariae: Onchocerca spp
- Intestinal threadworms (adults): Strongyloides westeri
- Summer Sores caused by Habronema and Draschia spp. cutaneous third-stage larvae
- Stomach bots: Oral and gastric stages of Gasterophilus intestinalis, and Gasterophilus nasalis
*Can be slightly different in some countries: read the product label!
- 91 mcg ivermectin per lb = 200 mcg ivermectin /kg bw, equivalent to 1 ml/50 kg (=110 lb) bw.
- Each 21 oz (6.08 G) syringe contains sufficient paste to treat one 1250 lb horse at the recommended dose rate.
- Each weight marking on the syringe plunger delivers enough paste to treat 250 lb body weight.
- LD50 (acute oral) in rats: ~1330 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
Suspected poisoning? Read the articles on ivermectin safety in this site.
Withholding periods (=withdrawal times) for meat & milk (country-specific differences may apply: read the product label)
- MEAT: USA: Do not use in horses intended for human consumption.
- MILK: USA: Do not use in animals producing milk for human consumption
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.
- Parascaris equorum: Resistance to macrocyclic lactones (e.g. ivermectin, moxidectin) has been reported in the USA, UK 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.
Alternative chemical classes/active ingredients to prevent resistance of gastrointestinal roundworms through product rotation:
- Benzimidazoles, mainly fenbendazole, mebendazole, etc. But they also have similar or even worse resistance problems than macrocyclic lactones
- 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.
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 product is marketed: USA
GENERIC BRANDS available? YES, worldwide by the dozens.
Click here to learn more about GENERIC vs. ORIGINAL drugs.
This product is a classic oral paste for horses from DURVET, a generic version of EQVALAN = ZIMECTERIN oral paste for horses from MERIAL.
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.).
Ivermectin is ineffective against tapeworms, this is why many horse wormers contain a mixture of a nematicide that controls roundworms (e.g. ivermectin, moxidectin, pyrantel) with praziquantel, a tapeworm-specific compound.
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.