Brand: TOPDEC Pour-on

Company: AGSURE


FORMULATION: «pour-on» for topical administration. To be applied along the topline in a narrow strip extending from the withers to the tailhead.

ACTIVE INGREDIENT(S): moxidectin: 5 mg/mL (=0.5%)

CHEMICAL CLASS of the active ingredient(s): macrocyclic lactone


INDICATIONS: CATTLE

PARASITES CONTROLLED* (spectrum of activity)

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


RECOMMENDED DOSE*

  • Cattle: 500 mcg/kg bw, equivalent to 1 ml/10 kg (=22 lb) bw
  • Read the product label for further details on dosing.

* Can be slightly different in some countries: read the product label!


SAFETY

  • LD50 (acute oral) in rats: >5000 mg/kg (estimate)
  • LD50 (acute dermal) in rats: 2870 mg/kg (estimate)
  • Estimated hazard class according to the WHO: not applicable for veterinary medicines

Suspected poisoning? Read the article on moxidectin safety in this site.

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

  • Meat: Australia NIL.
  • Milk: Australia NIL.

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:


RESISTANCE PREVENTION

Risk of resistance? YES, reported in gastrointestinal roundworms in cattle in several countries particularly in the following worm species: Cooperia spp and Ostertagia spp.

Resistance of gastrointestinal roundworms to macrocyclic lactones in sheep, goats and cattle has been reported in numerous countries. Most cases have been reported for ivermectin, and moxidectin often works well against ivermectin-resistant worms initially. But if moxidectin use continues gastrointestinal roundworms will become resistant to it rather quickly. Based on the very abundant and frequent use of ivermectin and other macrocyclic lactones in livestock (with more-or-less cross-resistance to ivermectin) it must be assumed that resistance of gastrointestinal 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.

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.

Resistance of cattle ticks Rhipicephalus (Boophilus) microplus to ivermectin, another macrocyclic lactone 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 unless specific resistance preventative measures (e.g. rotation, IPM, etc.) are taken.

Learn more about resistance and how it develops.


MARKETING

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

  • 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
GENERIC BRANDS available? YES, many brands in some countries (e.g. Australia), rather few, if at all, in other countries (e.g. the EU, USA).

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

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


COMMENTS

Moxidectin is a macrocyclic lactone introduced in the 1990s (by AMERICAN CYANAMID). It is moderately used in livestock and pets, but not in agriculture. Its spectrum of activity is similar to the one of  ivermectin, i.e. basically roundworms and certain external parasites (mites, lice, etc.). As all other macrocyclic lactones moxidectin is not effective against tapeworms and flukes. Moxidectin is generally considered as more potent than ivermectin against gastrointestinal nematodes of livestock, particularly in sheep and goats, and against a few other livestock pests (e.g. sheep scab, cattle ticks, etc.). It is also less toxic than ivermectin, which makes it possible to use it at higher rates, particularly in long-acting formulations. Moxidectin is moderately used in livestock and horses, but rather scarcely in pets. It is not used in agriculture.

Moxidectin is generally considered as more potent than ivermectin against gastrointestinal nematodes of livestock, particularly in sheep and goats, and against a few other livestock pests (e.g. sheep scab, cattle ticks, etc.). It is also less toxic than ivermectin, which makes it possible to use it at higher rates, particularly in long-acting formulations.

Besides convenience aspects, the moxidectin pour-on formulation has the advantage over the injectables that it also controls horn flies and biting lice, which are not controlled by the injectables.

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 and other macrocyclic lactone in gastrointestinal roundworms.

To our knowledge similar studies have not been carried out with the moxidectin pour-ons, but it must be assumed that the licking-behavior of cattle affects intake of moxidectin 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.

In contrast with the injectables, 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.

There are other moxidectin formulations for injectable or for oral (drench) administration, mainly for cattle and sheep. So far there are no moxidectin products for use on swine.

Being an excellent antiparasitic, comparable to ivermectin, moxidectin 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 moxidectin pour-on (without additional active ingredients) used at the recommended dose of 500 mcg/kg DOES NOT CONTROL:

Click here for general information on good practices for the prevention and control of gastrointestinal worms in livestock.


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.