Brand: COMBO™ LOW DOSE

Company: RAVENSDOWN


DELIVERY FORM: «drench» for oral administration.

ACTIVE INGREDIENT(S):

  • Levamisole hydrochloride 80 g/L (equivalent to 8.0%)
  • Oxfendazole 45.3 g/L (equivalent to 4.53%)
    • 0.9 g/L selenium; 0.2 g/L cobalt, 2.0 g/L copper; 0.6 g/L zinc: 0.9 g/L iodine: without any anthelmintic efficacy

CHEMICAL CLASS of the active ingredient(s):


INDICATIONS: SHEEP & CATTLE


PARASITES CONTROLLED* (spectrum of activity)

* Country differences may apply: read the product label!

Sheep

Cattle


RECOMMENDED DOSE

1 ml product per 10 kg bodyweight, equivalent to:

  • 4.53 mg/kg oxfendazole
  • 8 mg/kg levamisole hydrochloride (6.8 mg levamisole)

Read the product label for further details on dosing


SAFETY

  • LD50 (acute oral) in rats:
    • Oxfendazole: >6400 mg/kg (for the a.i.)
    • Levamisole: 180 mg/kg (for the a.i.)

Suspected poisoning? Read the articles on oxfendazole safety and levamisole safety in this site.

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

  • Meat: New Zealand, Sheep & Cattle 14 days
  • Milk for human consumption: New Zealand, Sheep & Cattle: Milk intended for sale for human consumption must be discarded during treatment and for not less than 35 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:


RESISTANCE PREVENTION

Risk of resistance? YES

Unfortunately, resistance of several gastrointestinal roundworms to oxfendazole (and other benzimidazoles) and levamisole is already very high and very frequent worldwide in sheep and goats. Cases of multiple resistance (i.e. simultaneous) to two or even three of these chemical classes have also been reported. Most affected worm species are:

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:

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.

Learn more about resistance and how it develops.


MARKETING

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

  • Oxfendazole: GENERIC (introduced in the 1970s)
  • Levamisole: GENERIC (introduced in the 1960s)

*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, in Australia and New Zealand, not elsewhere. This product itself contains generic active ingredients.

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

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


COMMENTS

COMBO LOW DOSE is a drench brand from RAVENSDOWN combining 2 active ingredients with different modes of action against gastrointestinal worms: oxfendazole and levamisole hydrochloride.

Oxfendazole is a veteran benzimidazole introduced in the 1970s (by WELLCOME, SYNTEX). It has a broad-spectrum of activity against roundworms (gastrointestinal and pulmonary) and tapeworms (dose-dependent) but is ineffective against flukesOxfendazole also kills eggs of roundworms (ovicidal activity). As all benzimidazolesoxfendazole has no efficacy whatsoever against external parasites (ticksflies, lice, mites, etc). Among the benzimidazoles oxfendazole is quite comparable with fenbendazole in terms of efficacy and safety. It is moderately used in livestock and horses, rather scarcely in pets, and not at all in agriculture.

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 (ticksflies, lice, mites, etc). Levamisole has been used massively worldwide in countless generic formulations. 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.

Oxfendazole and levamisole administered as a drench have no residual effect, i.e. they kill the parasites shortly after administration, but do not significantly protect the animals against re-infestation by infective stages in their environment.

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.

Thoroughly shaking suspensions before use is crucial for efficacy. If the active ingredient remains in the sediment, a few animals may get most of the active ingredient and will be overdosed, and the large majority will get almost only solvents and will be underdosed.

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.