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Brand: AVOMEC ® DUEL

Company: MERIAL


DELIVERY FORM: «drench» for oral administration.

ACTIVE INGREDIENT(S):

CHEMICAL CLASS of the active ingredient(s):


INDICATIONS: SHEEP


PARASITES CONTROLLED (spectrum of activity)

Sheep

  • Barber’s Pole Worm: Haemonchus contortus - including inhibited L4 stage and strains with single, dual or triple resistance to macrocyclic lactones, benzimidazoles, levamisole or closantel, and strains with emerging resistance to closantel.
  • Small Brown Stomach Worm: Teladorsagia (Ostertagia) circumcincta - including inhibited L4 stage and strains with single or dual resistance to macrocyclic lactones, benzimidazoles or levamisole:
  • Black Scour Worm: Trichostrongylus colubriformis - including strains with single or dual resistance to macrocyclic lactones, benzimidazoles or levamisole.
  • Large Stomach Worm: Haemonchus placei
  • Stomach Hair Wor: Trichostrongylus axei
  • Black Scour Worm: Trichostrongylus vitrinus
  • Small Intestinal Worm: Cooperia spp
  • Thin-Necked Intestinal Worm:  Nematodirus spp
  • Large Mouthed Bowel Worm: Chabertia ovina
  • Nodule Worm: Oesophagostomum columbianum
  • Large Bowel Worm: Oesophagostomum venulosum
  • Whip worm: Trichuris ovis
  • Intestinal threadworm: Strongyloides papillosus
  • Hookworm: Bunostomum spp
  • Lungworm: Dictyocaulus filaria (Large lungworm)
  • Liver Fluke: Fasciola hepatica - mature fluke and late immature forms including 6 week old stages.
  • Nasal Bot: Oestrus ovis
  • Itch mites: Psorergates ovis.

RECOMMENDED DOSE*

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

1 ml product per 5 kg bodyweight, equivalent to 0.2 mg/kg abamectin and 10 mg/kg closantel.

Liveweight (kg) Dose (mL) 5 L treats
11-15 3 1666
16-20 4 1250
21-25 5 1000
26-30 6 833
31-35 7 714
36-40 8 625
41-50 10 500
51-60 12 416
61-70 14 357
71-80 16 312

SAFETY

  • LD50 (acute oral) in rats:
    • Abamectin: 10 mg/kg (for the a.i.)
    • Closantel: 342 mg/kg (for the a.i.)

Suspected poisoning? Read the articles on abamectin safety, albendazole safety, closantel safety and levamisole safety in this site.

Withholding periods (=withdrawal times) for meat & milk (country-specific differences may apply: read the product label)

  • Meat: 49 days (ESI 84 days)
  • Milk for human consumption: Do not use in female sheep which are producing, or may in the future produce, milk or milk products for human consumption.  

RESISTANCE PREVENTION

Risk of resistance? YES

Unfortunately, resistance of several gastrointestinal roundworms to abamectin (and other macrocyclic lactones) is already very high and very frequent worldwide in sheep and goats. Resistance to closantel is emerging.

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 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 may 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:

These alternative products may not be available in all countries, or may not be available as drenches, 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.

Resistance of liver flukes (Fasciola hepatica) to closantel is still rare.

Learn more about resistance and how it develops.


MARKETING

Are the active ingredients of this product ORIGINAL* or GENERICS**?

  • Abamectin: GENERIC (introduced in the 1980s)
  • Closantel: GENERIC (introduced in the 1970s)

*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: AUS
GENERIC BRANDS available? Rather few, if at all, with this particular composition.

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

For an overview on the most used drench brands for livestock click here.


COMMENTS

AVOMEC DUEL is a drench brand from MERIAL combining 2 active ingredients with different modes of action against gastrointestinal worms of sheep: abamectin and closantel.

Abamectin, a veteran endectocide introduced in the 1980s (by MSD-AgVet), is considered as the "cheap" macrocyclic lactone. It is less potent and more toxic than ivermectin and other macrocyclic lactones but is often "good enough", although usually with a slightly narrower spectrum of efficacy and shorter protection periods than other macrocyclic lactones. Interestingly, abamectin is widely used in livestock in Australia and New Zealand but not at all in the EU, the USA and Canada. As for other macrocyclic lactones, abamectin has no efficacy whatsoever against tapeworms and flukes.

Closantel (introduced in the 1970s by JANSSEN) is a narrow spectrum but rather particular anthelmintic, because it is effective against some internal parasites (e.g. Haemonchus contortus and Fasciola hepatica) and a few external parasites as well (e.g. nasal bots). Closantel offers also good control of adult liver flukes, but efficacy against immatures is incomplete (>5 weeks ~90%; 3-4 weeks <73%): this is important because immature stages are the most damaging ones. Efficacy against roundworms is usually limited to blood-feeding species. This is related to the fact that ingested closantel is quickly absorbed to blood where it binds strongly to plasma proteins. There it remains for several days before being excreted. In contrast, its concentration in the tissues is usually too low to kill worms that do not feed blood, which are the majority among the roundworms that infect sheep. Nowadays closantel is scarcely used in most countries.

In ruminants, reducing the amount of feed slows down the exit flow of the rumen and prolongs the time during which the active ingredient remains there and is absorbed. Consequently it is advisable to reduce the access of animals to feed (especially to fresh pasture, not to water) 24 hours before administration. For the same reason, it is better to keep the animals away from food for about 6 hours after drenching. However sick or weak animals should not be kept away from food and fasting animals should have access to water.


DISCLAIMER

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.

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