Brand: ECLIPSE ® Pour-on for Cattle


FORMULATION: «pour-on» for topical administration. To be applied along the back line of the animal in a strip starting between the shoulder blades.


CHEMICAL CLASS of the active ingredient(s):


PARASITES CONTROLLED* (spectrum of activity)

* Country-specific differences may apply: read the product label.



  • LD50 (acute oral) in rats:
    • abamectin: a.i. 10 mg/kg (according to MSDS)
    • levamisole: a.i. 180 mg/kg
  • LD50 (acute dermal) in rats:
    • abamectin: a.i. 330 mg/kg (according to MSDS)
    • levamisole: a.i. n.a.
  • 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: Australia 56 days (ESI 70 days), New Zealand 35 days
  • Milk for human consumption: Australia: DO NOT USE in dairy animals producing or which will in the future be producing milk for human consumption. New Zealand: 35 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:


Risk of resistance of gastrointestinal roundworms to macrocyclic lactones (incl. abamectin) and levamisole: YES, worm resistance in cattle has been reported in numerous countries, particularly in the following worm species: Cooperia spp and Ostertagia spp.

Resistance of gastrointestinal roundworms to macrocyclic lactones (incl. abamectin) in sheep, goats and cattle has been reported almost worldwide, including the USA, UK, Australia and New Zealand. 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. The same applies basically to levamisole.

From the point of view of resistance prevention & management, products such as this one combining active ingredients of two different chemical classes (with different mechanisms of action) make sense when used against parasites that are still susceptible to both chemical classes. In this case it is assumed that simultaneous development of resistance to two different mechanisms of action is less likely to occur than to a single mechanism.

If the parasites are already resistant to one of the chemical classe in the combination, the main benefit of such combinations is short-term peace of mind for producers: if one compound fails, the other one will do the job. However if resistance to one chemical class has already developed, best practice (besides other Integrated Pest Management measures) is to change to another chemical class with a different mechanism of action and to stop using the chemical class to which parasites are already resistant. Otherwise the risk is significant that the parasites become multi-resistant, i.e. simultaneously resistant to both chemical classes. And this can happen within a few years. Multi-resistant worms are not yet widespread in cattle, but cases have been reported (e.g. in Argentina, the US and Europe; mainly to benzimidazole + macrocyclic lactones, and to benzimidazoles + levamisole).

In sheep and goats multi-resistance is already widespread in most traditional sheep-growing countries. There are e.g. reports from Brazil (2010) about gastrointestinal roundworms (Haemonchus spp, Trichostrongylus spp, and Ostertagia spp) resistant to up to 9 active ingredients of 7 different chemical classeslevamisole (imidazothiazole), albendazole (benzimidazole), ivermectin and moxidectin (macrocyclic lactones), nitroxinil, disophenol, trichlorfon (organophosphates) and closantel (salicylanilide), including the combination of levamisolealbendazole and ivermectin.

Alternative chemical classes/active ingredients to prevent resistance of gastrointestinal roundworms through product rotation:

These alternative products may not be available in all countries, or may not be available as pour-ons.

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: Australia, New Zealand
GENERIC BRANDS available? Not yet in most countries in this particular composition and as a pour-on. Comparable combinations may be available as oral drenches.

Click here to learn more about GENERIC vs. ORIGINAL drugs.

For an overview on the most used antiparasitic pour-on brands click here.


ECLIPSE Pour-on for cattle from MERIAL (now BOEHRINGER INGELHEIM) is one of the few pour-ons for cattle combining two anthelmintics with different mechanisms of action. Such combinations are very widely used as drenches, particularly on sheep, where resistance problems are more dramatic than on cattle.

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 a veteran generic anthelmintic introduced already in the 1960s, and massively used on livestock worldwide since the 1990s. Its spectrum of efficacy against gastrointestinal roundworms and lungworms is similar to that of abamectin, but is not effective against inhibited larvae of Ostertagia spp. Otherwise levamisole has no efficacy whatsoever on tapeworms and flukes, nor on any external parasites of cattle. The only benefit ot adding it to abamectin is hoping that if abamectin fails to control gastrointestinal roundworms (particularly Cooperia spp and Ostertagia spp) due to resistance, levamisole will do the job. See previous comments regarding resistance prevention.

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 lactones in gastrointestinal roundworms.

To our knowledge similar studies have not been carried out with the abamectin or levamisole pour-ons, but it must be assumed that the licking-behavior of cattle affects intake of both compounds in a comparable way. A similar effect of the licking behavior of cattle 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 (drench). 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.

The different withholding periods in various countries illustrate the fact that unfortunately, national regulatory authorities often draw different conclusions from exactly the same scientific evidence. This has been always so and there are no indications that things will improve in the near future.

For these reasons efficacy after pour-on administration is usually less reliable than after injection or oral administration (drench).


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.