Brand: NITROFLUKE ® Injection

Company: VIRBAC

FORMULATION: «injectable» to be administered subcutaneously under the loose skin in front of, or behind the shoulder in cattle.


CHEMICAL CLASSES of the active ingredient(s):

  • Clorsulon: Benzenesulphonamide
  • Nitroxynil: halogenated phenol


PARASITES CONTROLLED (spectrum of activity)

  • Liver flukes, Fasciola hepatica, early immatures (including 2-week old), immatures and adults.


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

  • 1.5 ml product/50 kg (=110 lb) bw, corresponding to:


  • LD50 (acute oral) in rats:
    • closulon a.i. >10000 mg/kg (according to MSDS)
    • nitroxynil a.i. 170-450 mg/kg (for various salts)
  • LD50 (acute dermal) in rats:
    • clorsulon a.i. n.a.
    • nitroxynil a.i. n.a.
  • Estimated hazard class according to the WHO: not applicable for veterinary medicines

Suspected poisoning? Read the articles on clorsulon safety and nitroxinil safety in this site.

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

  • Meat: 70 days (ESI = 210 days).
  • Milk: Do not use in female animals which are producing or may in the future produce milk or milk products for human consumption

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? Low

There are a few reports on liver fluke (Fasciola hepatica) resistance to clorsulon in sheep, but so far it seems to be rather unusual. To our knowledge there are no published reports on resistance of liver fluke (Fasciola hepatica) to clorsulon or nitroxynil in cattle.

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 product is marketed (maybe under another TM) Australia
GENERIC BRANDS available? YES, perhaps not with the same composition.

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

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


NITROFLUKE INJECTION for Cattle from VIRBAC is a rather unusual combination of generic clorsulon and nitroxynil.

Clorsulon is a veteran flukicide introduced in the 1970s (by MS&D-AGVET), a benzenesulphonamide with a narrow spectrum of efficacy against a few trematode species. It has no efficacy whatsoever on roundworms (gastrointestinal, pulmonary, ocular, etc.) or tapeworms, nor on external parasites of cattle (mites, lice, ticks, grubs, etc). It is moderately used in cattle, not at all in sheep, goats, horses, swine or poultry. It is not used in agriculture.

Nitroxynil is a narrow spectrum anthelmintic, introduced in the 1960s (by MAY & BAKER). It is effective against liver flukes and a few gastrointestinal  roundworms . It is completely ineffective against external parasites. It is scarcely used in ruminants, not at all in horses, swine, poultry or pets. It is not used in agriculture.

The reason for combining clorsulon with nytroxynil is strengthening the efficacy against liver flukes (Fasciola hepatica).


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.