Brand: PARAMECTIN ® 0.5% Pour-on Solution
PARASITES CONTROLLED* (spectrum of activity)
* Country-specific differences may apply: read the product label.
- Gastrointestinal roundworms (adults and L4 larvae): Ostertagia ostertagi (incl. inhibited larvae), Haemonchus placei, Trichostrongylus axei, Trichostrongylus colubriformis, Cooperia spp, Oesophagostomum radiatum, Strongyloides papillosus (adults only), Trichuris spp (adults only).
- Lungworms (adults and L4 larvae): Dictyocaulus viviparus.
- Eyeworms: Thelazia spp (adults only).
- Cattle grubs (warbles, parasitic stages): Hypoderma bovis, Hypoderma lineatum.
- Sucking & biting lice: Linognathus vituli, Haematopinus eurysternus, Bovicola (Damalinia) bovis.
- Mites (scabies): Sarcoptes scabiei var. bovis, Chorioptes bovis.
- Horn flies: Haematobia irritans.
*Can be slightly different in some countries: read the product label!
- Cattle: 500 mcg/kg bw, equivalent to 1 ml/10 kg (=22 lb) bw
- LD50 (acute oral) in rats: 10000 mg/kg (estimate)
- LD50 (acute dermal) in rats: >100000 mg/kg (estimate)
- Estimated hazard class according to the WHO: not applicable for veterinary medicines
Suspected poisoning? Read the article on ivermectin safety in this site.
Withholding periods (=withdrawal times) for meat & milk (country-specific differences may apply: read the product label)
- Meat: UK, Ireland 28 days
- Milk for human consumption: Ireland; This product should not be used in cattle producing milk for human consumption. The product should not be used in
non-lactating dairy cows including pregnant heifers within 60 days of calving.
WARNING !!!: Never use on humans, dogs and 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
Based on the very abundant and frequent use of ivermectin and other macrocyclic lactones (with cross-resistance to ivermectin) in livestock it must be assumed that resistance of these roundworms to this chemical class will continue spreading and strengthening in the future.
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.
- Benzimidazoles, e.g. albendazole, febantel, fenbendazole, oxfendazole, etc. Similar or even worse resistance problems than ivermectin
- Imidazothiazoles, mainly levamisole. etc. Similar or even worse resistance problems than ivermectin
- Nitroxinil (limited spectrum of activity)
- Tetrahydropyrimidines, e.g. morantel, pyrantel (limited spectrum of activity)
- Salicylanilides, e.g. closantel (limited spectrum of activity)
These alternative products may not be available in all countries, or may not be available as pour-ons.
Resistance of cattle ticks Rhipicephalus (Boophilus) microplus to ivermectin has been reported in several Latin American countries. It is not yet a widespread problem, but nevertheless a warning. Based on the intensive use of macrocyclic lactones on cattle it is only a matter of time for resistance of cattle ticks to these compounds to develop elsewhere.
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 (maybe under another TM): UK, Ireland and other EU countries
GENERIC BRANDS available? YES, worldwide by the dozens. This brand itself contains generic ivermectin.
Click here to learn more about GENERIC vs. ORIGINAL drugs.
For an overview on the most used antiparasitic pour-on brands click here.
PARAMECTIN 0.5% Pour-on Solution for cattle from NORBROOK is a generic version of MERIAL's IVOMEC Pour-on for cattle.
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.
Besides convenience aspects, the ivermectin pour-on formulation has the advantage over the ivermectin 1% injectable that it also controls horn flies and biting lice, which are not controlled by the 1% injection.
But it has also disadvantages. In several scientific studies it has been shown that ivermectin administered as a pour-on is not "automatically" absorbed through the skin. Licking (self licking or licking of other treated animals) may account for >50% of the total intake, compared with only about 10% absorbed directly through the skin. This is the reason why a dose of 500 mcg/kg bw is needed after pour-on treatment, compared with only 200 mcg/kg bw after injection. And it has been also shown that intake of topically administered active ingredient in some cattle may be twice as high as in other ones, all treated at the same rate. The reason is that individual cattle show a different licking behavior. An important practical consequence is that the quantity that is finally ingested and is therefore available for the control of gastrointestinal worms depends on the licking behavior of the treated animals. "High lickers" can be overdosed, whereas "low lickers" can be underdosed. And chronic underdosing of animals in a herd may enhance development of resistance to ivermectin in gastrointestinal roundworms.
Absorption through the skin is also negatively affected by the thickness of the skin and the hair coat, by dust and mud on the coat, by product lost on fences and yards, etc, factors that don't play a role after injection.
In contrast with the ivermectin 1% injectable, the pour-on formulation should not be administered to wet animals, and rain shortly before (up to 6 hours) or after administration can cause product run-off and thus under-dosing. The pour-on shouldn't be administered by strong winds that may blow away part of the product and/or contaminate the workers.
For all these reasons efficacy after pour-on administration is usually less reliable than after injection.
It is good to know that not all ivermectin 1% injectable formulations are exactly the same as the original formulation (IVOMEC Pour-on). There are studies showing that the protective period (residual effect) against some particular parasites is considerably different among such formulations, indicating that they are not really bioequivalent. This can be due to different non-active ingredients in the formulation, different qualities of the active ingredient (e.g. with different by-products), different manufacturing processes, etc. Usually this is considered by the regulatory authorities of each country that issue the approved use instructions of every product, which may be different. It is also important to understand that although the product may control certain parasites, they may not be mentioned in the indications in a particular country simply because they do not occur there: e.g. cattle grubs in Australia and South America, human bot flies in Europe, North America and Australia, etc.
Being one of the best antiparasitics ever developed, ivermectin does not control all parasites of livestock. Unfortunately advertising and even the label of some generic formulations in less developed countries often include unsubstantiated claims. To help preventing confusion and misuse it is useful to know that whatever ivermectin 0.5% pour-on formulation (without additional active ingredients) used at the recommended dose DOES NOT CONTROL:
- Most ticks (e.g. Amblyomma spp, Rhipicephalus spp, Dermacentor spp, Haemaphysalis spp, Hyalomma spp, Ixodes spp, etc.)
- Flies other than horn flies (e.g. houseflies, stable flies, black flies, horse flies, etc.)
- Fleas (e.g. Ctenocephalides spp)
- Tapeworms (e.g. Moniezia spp)
- Flukes (e.g. liver fluke Fasciola hepatica)
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