FORMULATION: «injectable» solution to be administered subcutaneously.

ACTIVE INGREDIENT(S): eprinomectin 10 mg/mL (=1%)

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


PARASITES CONTROLLED* (spectrum of activity)

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


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

  • 1 ml product per 50 kg bw, equivalent to 200 mcg/kg bw

Read the product label for further details on dosing


  • LD50 (acute oral) in rats: ~55 mg/kg for the a.i.
  • Estimated hazard class according to the WHO: not applicable for veterinary medicines

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

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

  • Meat: New Zealand 14 days.
  • Milk for human consumption: New Zealand NIL.

WARNING !!!: Never use on humans, dogs and cats


Risk of resistance? YES, reported for ivermectin in gastrointestinal roundworms in cattle in several countries, particularly in the following worm species: Cooperia spp, Ostertagia spp, Haemonchus spp, Trichostrongylus spp, Oesophagostomum spp, whereby cross-resistance between eprinomectin and ivermectin must be assumed.

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.

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 injectables.

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 (maybe under another TM): New Zealand
GENERIC BRANDS available? YES, but rather few and not in all countries. This brand itself contains generic eprinomectin.

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

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


EPRIJECT injection for cattle from HORIZON AGRESOURCES is one of the so far few eprinomectin injectables for cattle, after MERIAL's LONGRANGE (5% eprinomectin injectable) not yet available everywhere.

Eprinomectin was one of the last macrocyclic lactones introduced in the 1990s (by MERIAL). It was the first macrocyclic lactone approved for use on dairy cows because it does not leave significant residues in milk, in contrast with all ivermectin-based products. Nowadays other macrocyclic lactones (e.g. doramectin, moxidectin) have been approved for use on dairy cows in some countries. The spectrum of activity of eprinomectin is similar to that of ivermectin and other macrocyclic lactones: mainly roundworms, lice and mites and, delivered as a pour-on, also some fly and tick species. It is ineffective against tapeworms and flukes. Eprinomectin is moderately used in cattle but not in other livestock. It is marginally used in cats, but not in dogs. It is not used in agriculture.

Being an excellent antiparasitic, comparable to ivermectin, eprinomectin 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 eprinomectin 0.5% pour-on formulation (without additional active ingredients) used at the recommended dose DOES NOT CONTROL:


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