Brand: OUTLAW POUR-ON
Company: ELANCO (BAYER)
FORMULATION: «pour-on» for topical administration.
- Abamectin: 10 mg/mL =1%
- Levamisole hydrochloride 200 mg/mL (equivalent to 20.0%)
CHEMICAL CLASS of the active ingredient(s)
- Abamectin: macrocyclic lactone
- Levamisole: imidazothiazole
INDICATIONS: CATTLE (Beef & dairy)
PARASITES CONTROLLED* (spectrum of activity)
* Country differences may apply: read the product label!
- Gastrointestinal roundworms:
- Adult worms and immature stages of: Ostertagia ostertagi (incl. inhibited L4 larvae), Ostertagia lyrata (incl. inhibited L4 larvae), Haemonchus spp, Trichostrongylus axei, Trichostrongylus longispicularis, Cooperia oncophora, Cooperia surnabada & Cooperia punctata (incl. inhibited L4 larvae), mature Trichuris spp.
- Lungworms adult & immature: Dictyocaulus viviparus.
- Sucking & biting lice: Haematopinus eurysternus, Linognathus vituli, Bovicola (Damalinia) bovis.
- 1 ml product/20 kg, equivalent to: abamectin 0.5 mg/kg bw and levamisole 10 mg/kg bw
Read the product label for further details on dosing.
- Abamectin: 10 mg/kg (for the a.i.)
- Levamisole: 180 mg/kg (for the a.i.)
- Estimated hazard class according to the WHO: not applicable for veterinary medicines
Suspected poisoning? Read the articles on abamectin safety and levamisole safety in this site.
Withholding periods (=withdrawal times) in days for meat & milk (country-specific differences may apply: read the product label)
- Meat: New Zealand 42 days
- Milk: New Zealand: Milk intended for sale for human consumption must be discarded during treatment and for not less than 42 days following the last treatment.
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
Unfortunately, resistance of several gastrointestinal roundworms to abamectin (and other macrocyclic lactones) and levamisole is already very high and very frequent worldwide in sheep and goats, less in cattle. Cases of multiple resistance (i.e. simultaneous) to two or even three of these chemical classes have also been reported. Most affected worm species in cattle are: Cooperia spp, Ostertagia spp, Haemonchus spp, Trichostrongylus spp, Oesophagostomum spp.
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.
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.
Alternative chemical classes/active ingredients to prevent resistance of gastrointestinal roundworms through product rotation:
- Benzimidazoles, e.g. albendazole, febantel, fenbendazole, oxfendazole, etc. Similar or even worse resistance problems than ivermectin
- Salicylanilides (e.g. closantel): effective only against certain gastrointestinal roundworms. Not available in some countries. Resistance to closantel has been reported in some countries.
- Tetrahydropyrimidines (e.g. morantel, pyrantel): effective only against certain gastrointestinal roundworms. Not available in some countries. Resistance to morantel has been reported in some countries.
- Nitroxinil: effective only against certain 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 available as pour-ons, 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.
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: New Zealand
GENERIC BRANDS available? Yes, several in Australia and New Zealand, not in the USA or Europe.
Click here to learn more about GENERIC vs. ORIGINAL drugs.
For an overview on the most used antiparasitic pour-on brands click here.
OUTLAW Pour-on for cattle from BAYER (now ELANCO) is a classic pour-on combining 2 generic active ingredients with different modes of action against gastrointestinal worms: abamectin and levamisole hydrochloride.
Abamectin, one of the first macrocyclic lactones developed, was introduced already in the 1980s (by MSD AGVET). As all macrocyclic lactones, abamectin is an endectocide, i.e. it is simultaneously effective against some external parasites and against internal parasites (mainly roundworms). As for other macrocyclic lactones, abamectin has no efficacy whatsoever against tapeworms and flukes. Abamectin is considered as the "cheap" ivermectin, with a similar spectrum of efficacy but less potent and slightly more toxic. It is abundantly used in ruminants, much less in pig, poultry and pets. Abamectin is also used in agricultural and hygiene pesticides worldwide. Interestingly abamectin is widely used on livestock in Australia and New Zealand but insignificantly in the EU, the USA and Canada.
Levamisole is the most veteran anthelmintic in this combination. It was introduced by JANSSEN already in the 1960s (NILVERM, RIPERCOL). It has a broad-spectrum of activity against roundworms (gastrointestinal and pulmonary) but no efficacy whatsoever against tapeworms and flukes. It is also completely ineffective against external parasites of livestock (ticks, flies, lice, mites, etc). Levamisole has been used massively worldwide in countless generic formulations, mostly in drenches, injectables and feed feed additives, and to a smaller extent also in pour-ons. It still remains one of the most preferred low-cost anthelmintics for livestock worldwide. It is only marginally used in horses and pets. It is not used in agriculture.
It is useful to know that pour-on administration of parasiticides has some disadvantages when compared with injectables and drenches. 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 and other macrocyclic lactone in gastrointestinal roundworms.
To our knowledge similar studies have not been carried out with abamectin pour-ons, but it must be assumed that the licking-behavior of cattle affects intake of abamectin in a comparable way. A similar effect of the licking behavior on the intake of active ingredient after pour-on administration has also been shown for fluazuron, a tick development inhibitor.
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 or oral administration. 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 these reasons efficacy after pour-on administration is usually less reliable than after injection or oral administration (mostly drench).
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.
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