Company: NEXAN

FORMULATION: «pour-on» for topical administration.

ACTIVE INGREDIENT(S)triflumuron 25 g/L (= 2.5%)

CHEMICAL CLASS of the active ingredient(s): insect growth regulator (= IGR, benzoylphenyl urea)


PARASITES CONTROLLED* (spectrum of activity)

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


  • Control of body lice Bovicola (Damalinia) ovis on all breeds of sheep. Protects against the establishment of lice populations for up to 12 weeks.
  • Control of blowfly strike (inc. Lucilia cuprina) in coarse wool breeds of sheep.


* Read the product label for further details on dosing and administration.

Use recommendations (New Zealand):

  Lice Fly control
Sheep weight (kg) Dose rate (mL) Dose rate (mL)
≤10 10 2x5.0
10.1 - 20 12 2x6.0
20.1 - 30 15 2x7.5
30.1 - 55 20 2x10.0
55.1 - 75 25 2x12.5
>75 5 mL/10kg 2x2.5m/10 kg


  • LD50 (acute oral) in rats: for the a.i. >5000 mg/kg
  • Estimated hazard class of the a.i. according to the WHO classification of pesticides: U, unlikely to present acute hazard in normal use.

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

  • Meat: New Zealand: 49 days
  • Milk for human consumption: New Zealand: Milk intended for human consumption must be discarded for 35 days following the last treatment.
  • Shearing: New Zealand: 2 months.

You may be interested in the following articles in this site dealing with the general safety of veterinary products:


Risk of resistance? YES. Resistance reported in Australia in field populations.

Resistance of body lice Bovicola (Damalinia) ovis to triflumuron and other benzoylphenyl ureas has been reported in Australia, not yet in New Zealand.

Resistance of blowfly strike has been reported both in Australia and New Zealand. In Australia it is that high, that triflumuron and other benzoylureas are no more approved for blowfly strike control. For this reason efficacy of this product against sheep blowfly strike may not achieve the label claims.

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 for product rotation to prevent resistance of body lice to triflumuron:

These alternative products may not be available in all countries, or may not be available as pour-ons.

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: New Zealand.
GENERIC BRANDS available? YES, a few ones in Australia & New Zealand.

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

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


VETMED TRIFLUMAX for sheep is a classic pour-on from NEXAN with generic triflumuron, a generic version of BAYER's ZAPP.

Triflumuron is a broad-spectrum insect growth regulator (IGR) belonging to the benzoylphenyl-ureas introduced in the 1980s (by BAYER). It is effective against immature stages (larvae, nymphs, etc.) of numerous insects but not against adult stages. It is scarcely used in sheep and horses but only in Australia and New Zealand, not in Europe or the US. It is not used so far in other livestock or in pets. It is also used moderately against agricultural and household pests.

It is important to understand that this and other products containing insect growth regulators do not kill adult lice that may infect sheep at the moment of treatment, i.e. they don't have a knock-down effect. What they do is to interrupt further development of immature stages. Larvae and/or nymphs fail to molt to the next stage and die. Therefore they are used to prevent the further development of immature stages or eggs of occasional adult lice that sheep may catch.

Triflumuron and other benzoylphenyl ureas conquered the sheep body lice market very quickly in Australia and New Zealand after resistance to synthetic pyrethroids exploded and organophosphates that still worked well were progressively withdrawn for safety reasons.

It is interesting to know that neither triflumuron nor other benzoylphenyl ureas are used on sheep in the EU, the US or in Latin America, where body lice is also an important pest of sheep. The likely reason is that organophosphates and/or synthetic pyrethroids are still widely used in these countries against this pest that has not yet become resistant to these chemicals there.


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.