Synthetic insecticides, analogues of pyrethrins, but more potent and more stable in light. Considered less toxic than the natural compounds. Specific pyrethroids are used against ectoparasites.


Compounds in this category
Allethrin, alphamethrin, bioallethrin, bioresmethrin, cisrnethrin, cyalothrin, cyfluthrin, cypermethrin, deltamethrin, depallethrin, fenpropathrin, fenvalerate, flumethrin, fluvalinate, lambda-cyalothrin, permethrin, pybuthrin, resmethrin, tetramethrin.


[affected.gif] Animals most affected
Fish, dogs, (cattle).


[etiology.gif] Etiology


[toxic.gif] Toxicity
Extremely toxic to fish. Of low toxicity to birds and mammals as the chemicals degrade rapidly following ingestion.
The compounds with a cis-configuration are more toxic than those with a trans-configuration (cf permethrin). Toxic doses: see entries for individual compounds.


[clinical.gif] Clinical features
Non-specific, neuromuscular and gastrointestinal effects predominate:


Death may occur due to respiratory failure.


[lesions.gif] Lesions
Non-specific: hepatic and renal degeneration.


[treatm~1.gif] Treatment
No antidote. Symptomatic care only, promote excretion:



[labinv~1.gif] Laboratory investigations

Essential to have very fresh samples for analysis as the compounds degrade rapidly.