Cyfluthrin is an antiparasitic active ingredient used in veterinary medicine in livestock against external parasites (lice, mites, fleas, flies, ticks, etc.). It is also used against agricultural and household pests. It belongs to the chemical class of the synthetic pyrethroids.
EFFICACY AGAINST PARASITES
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.
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 parasite. Check the labels of the products available in your country for specific information on approved indications.
The table below indicates some usual dosing recommendations for cyfluthrin issued by manufacturers or documented in the scientific literature. They may not be approved in some countries.
Cyfluthrin is an excellent insecticide effective against many parasitic insects (e.g. horn & buffalo flies, stable flies, face flies, lice, etc) but not as good against cattle ticks and mites. It is completely ineffective against internal parasites.
As all synthetic pyrethroids, cyfluthrin products are always used for topical administration, in this case mainly in the form of ready-to-use products such as pour-ons or ear-tags for livestock or horses. Usage is nowadays rather scarce in livestock. It is not used in pets.
|Dosing recommendations for CYFLUTHRIN
|Delivery||Parasites||Dose (against cyfluthrin-susceptible parasites)
|Pour-on||Horn flies, face flies||0.2-0.9 mg/kg, dep. on animal's weight|
|Pour-on||Lice||0.4-1.8 mg/kg, dep. on animal's weight|
|Pour-on||Flies, lice||0.5-1 mg/kg, dep. on animal's weight|
|Pour-on||Flies, lice||0.5-1 mg/kg, dep. on animal's weight|
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Oral LD50, rat, acute*: 869-1271 mg/kg
Dermal LD50, rat, acute*: >5000 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.
WARNING: Most synthetic pyrethroids can be toxic for cats.
MRL (maximum residue limit) established 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 established also for agricultural pesticides that are not approved for use on animals but are used on commodities fed to animals. It may be also established 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 information on the safety of veterinary antiparasitics is available in specific articles in this site (click to visit):
- General safety of antiparasitics for domestic animals
- General safety of antiparasitics for humans
- General safety of antiparasitics for the environment
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!!!
MARKETING & USAGE
Decade of introduction: 1980
Introduced by: BAYER
Some original brands: BAYOFLY, SOLFAC
Patent: Expired (particular formulations may be still patent-protected)
Use in LIVESTOCK: Yes, moderate
use in HORSES: Yes, scarce
Use in DOGS: Yes, very scarce
Main delivery forms:
Use in human medicine: No
Use in public/domestic hygiene: Yes
Use in agriculture: Yes
Generics available: Yes, very few
In livestock & horses: Yes, as for all synthetic pyrethroids: very frequent worldwide in such species as horn flies (Haematobia irritans), sheep lice (Damalinia ovis), poultry mites (Dermanyssus gallinae), houseflies (Musca domestica), mosquitoes.
In pets: Yes, quite frequent worldwide in dog and cat fleas (Ctenocephalides spp).
Cyfluthrin is a synthetic pyrethroid particularly effective against insects (flies, lice, mosquitoes, etc.) but only mediocre against ticks and mites. As most synthetic pyrethroids, cyfluthrin is a mediocre larvicide, i.e. it is not indicated for the large-scale prevention of cutaneous myiases (e.g. screwworms, blowfly strike, etc.) with sprays, pour-ons, etc.
Cyfluthrin is a mixture of various optic isomers, but all commercial products contain the same mixture, i.e. this makes no difference in the product quality or efficacy.
Although patent has expired long ago, there are only a few generic veterinary products available.
However, resistance to cyfluthrin is widespread and can be very high in cattle ticks (Boophilus spp), horn flies (Haematobia irritans), red poultry mites (Dermanyssus gallinae), sheep lice (Damalinia ovis), houseflies (Musca domestica), dog and cat fleas (Ctenocephalides spp) and mosquitoes. As a consequence, products with cyfluthrin are already totally useless against these important parasites in many places.The same applies to all other synthetic pyrethroids (e.g. cypermethrin, deltamethrin, flumethrin, permethrin, etc.). And this is true for whatever delivery form: dipping, spraying, pour-ons, etc.
Pharmacokinetics of cyfluthrin
Topically administered cyfluthrin remains mostly on the hair-coat of the treated animals and is very poorly absorbed through the skin. In contrast with natural pyrethrins and older synthetic pyrethroids cyfluthrin is quite resistant to UV-light, which allows a residual effect between 5 and 10 days for most sprays and dips.
Treated animals can ingest cyfluthrin through licking or grooming. A large amount of it is excreted unchanged through the feces. The absorbed cyfluthrin is quickly metabolized in the liver to inactive metabolites that are excreted through urine. This is done by a specific enzyme called glucuronidase. However, cats lack this enzyme and cannot properly metabolize most synthetic pyrethroids. This is why most synthetic pyrethroids are toxic to cats.
As a general rule cyfluthrin products are approved for use on dairy animals in many countries.
Mechanism of action of cyfluthrin
Synthetic pyrethroids, including cyfluthrin, have a similar mode of action as organochlorines. They act on the membrane of nerve cells blocking the closure of the ion gates of the sodium channel during re-polarization. This strongly disrupts the transmission of nervous impulses. At low concentrations insects suffer from hyperactivity. At high concentrations they are paralyzed and die.
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