Fluazuron is an antiparasitic active ingredient used in veterinary medicine in cattle against ticks. It is not used against agricultural and household pests. It is a so-called Insect Growth Regulator (IGR) belonging to the chemical class of the benzoylphenyl ureas.

Common name: FLUAZURON

Type: pesticide
Chemical class: bezoylurea, tick development inhibitor


Molecular structure of FLUAZURON






Type of action: contact and systemic tickicide
Main veterinary parasites controlled: ticks

Efficacy against a specific parasite depends on the delivery form and on the dose administered. 

Click here for general information on features and characteristics of PARASITICIDES.


Fluazuron is a specific tick development inhibitor with systemic effect. It is abundantly used in cattle, mostly in pour-ons. So far it is not used in other livestock, horses or pets, nor against agricultural or household pests.

The table below indicates some usual dosing recommendations for fluazuron issued by manufacturers or documented in the scientific literature. They may not be approved in some countries.

Dosing recommendations for FLUAZURON
Delivery Parasites Dose (against fluazuron-susceptible parasites)
Pour-on Cattle ticks (Boophilus spp) 1.5 mg/kg (2.5 in Latin America). Preventive use recommended. No knock-down effect: needs ~3 weeks to clear infested cattle from ticks. 7-12 weeks protection dep on formulation, breed and cattle type.
Pour-on Amblyomma ticks 2.5 mg/kg. Only preventive use during the larval season.

DISCLAIMER: Liability is denied for any possible damage or harm to persons, animals or any other goods that could follow the transmission or use of the information, data or recommendations in this site by any site visitor or third parties.

Dosing recommendations for antiparasitics depend on national regulations. National regulatory authorities determine whether a product is approved for a given indication, i.e. use on a particular host at a specific dose and against a specific parasiteCheck the labels of the products available in your country for specific information on approved indications.

In most finished products, efficacy and safety depend not only on the amount of active ingredient(s) but also on their formulations (i.e. the type and amount of so-called inert ingredients), particularly in topical pour-ons and spot-ons. These inert ingredients can significantly affect the pharmacokinetic behavior (e.g. absorption through the skin, distribution within the body, spreading throughout the body surface, etc). Generic products usually contain the same amount of active ingredient(s) as the original product, but often in quite different formulations. In many cases, the curative (therapeutic) efficacy of the different formulations is quite comparable, but the protective (prophylactic) efficacy that determines the length of protection against re-infestations may be rather different.


Oral LD50, rat, acute*: >5000 mg/kg
Dermal LD50, rat, acute*: >2000 mg/kg
* These values refer to the active ingredient. Toxicity has to be determined for each formulation as well. Formulations are usually significantly less toxic than the active ingredients.

MRL (maximum residue limit) set for animal tissues (either beef, mutton pork or chicken)*:

  • CODEX: Yes
  • EU: Yes
  • USA: Yes
  • AUS: Yes

* This information is an indicator of the acceptance of an active ingredient by the most influential regulatory bodies for use on livestock. MRL's for animal tissues may be set also for agricultural pesticides that are not approved for use on animals but are used on commodities fed to animals. A MRL may be also set in the form of an IMPORT TOLERANCE for active ingredients not approved in a particular country but approved for imported animal commodities.

Withholding periods for meat, milk, eggs, etc. depend on delivery form, dose and national regulations. Check the product label in your country.

General safety information for antiparasitics is available in specific articles in this site (click to visit):


Never use agricultural or hygiene products with this or any other active ingredient on livestock or pets, even if there are veterinary products with this same active ingredient approved for use on animals. The formulations for agricultural or hygiene use are different and may be toxic for livestock or pets.

It is obvious that veterinary products are not intended for and should never be used on humans!!!


Decade of introduction: 1990
Some original brands: ACATAK
Patent: Expired (particular formulations may be still patent-protected)

Use in LIVESTOCK: Yes, moderate
Use in HORSES: No
Use in

Main delivery forms: 

Use in human medicine: No
Use in
public/domestic hygiene: No
Use in
agriculture: No
Generics available: 
Yes, a few


In livestock: YES. First reports on cattle tick (B. microplus) resistance in Australia (2010) and Brazil (2014).


Fluazuron is a tick development inhibitor belonging to the benzoylureas. In fact, it is the only tick development inhibitor currently in the market.

It is very specific and highly effective against ticks. It is available only as a pour-on for cattle, alone or in mixtures.

Efficacy of fluazuron

In contrast with all other benzoylureas (diflubenzuron ,lufenuron, triflumuron, etc.) that interfere with the development of insects, but not of ticks, at the therapeutic dose fluazuron interferes with the development of ticks, but not of insects.

It is effective against all major ticks that infest cattle (e.g. Amblyomma spp, Boophilus spp, etc.), but being a development inhibitor and not a tick killer it is especially useful for the control of single-host ticks such as cattle ticks (Boophilus spp) and not always useful against two-host or multi-host ticks.

Fluazuron inhibits the molt of tick larvae to nymphs and of nymphs to adults. Adult females treated with fluazuron may lay eggs but they will not hatch. As other development inhibitors, fluazuron is therefore appropriate as a preventative and for population control, but not for quick relief of already highly infested livestock. Administered to animals highly infested with Boophilus ticks it will need 3 to 4 weeks to eliminate the ticks.

Fluazuron is also highly effective against some poultry mites (e.g. Dermanyssus gallinae), but there are no commercial products for this indication.

Pharmacokinetics of fluazuron

Fluazuron has a systemic mode of action. After topical pour-on administration it is absorbed into blood, either through the skin or after licking. Once in the blood it is distributed throughout the whole body and is deposited in the fat tissues. This deposit is slowly released back to the bloodstream and reaches the ticks everywhere in the host's body. This allows maintaining the effective concentration in blood for up to 3 months.

Fluazuron is hardly metabolized. It is excreted slowly with a halftime of about 13 days, mainly through the feces.

Mechanism of action of fluazuron

As other Chitin Synthesis Inhibitors fluazuron hampers the synthesis and/or the correct deposit of chitin in the cuticle of ticks. As a consequence larvae or nymphs cannot properly molt and die during the molting process. Egg hatching is also interrupted due to the fact that young larvae developing inside the egg have to molt before hatching. If the adult female was treated with a chitin synthesis inhibitor significant amounts of it are passed to the eggs. The embryo can develop quite normally but it dies during the first molt, still inside the eggshell.

Click here to view the list of all technical summaries of antiparasitic active ingredients in this site.

A personal message

I was very heavily involved in the development and introduction of fluazuron (ACATAK) in the 1990s during my years in NOVARTIS AH.

Click here if you want to know more about the discovery, development and introduction of fluazuron and ACATAK.