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.
Animals most affected
Fish, dogs, (cattle).
accidental application or intentional treatment (e.g. mosquito eradication) of
stretches of water;
pollution through percolation into water courses (fish);
direct ingestion of the agrochemical product, of water run-offs or ditch water
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.
Non-specific, neuromuscular and gastrointestinal effects predominate:
motor incoordination, clonic convulsions, stiffness of the hind quarters;
tachycardia, cardiac fibrillation possible.
Death may occur due to respiratory failure.
Non-specific: hepatic and renal degeneration.
No antidote. Symptomatic care only, promote excretion:
adsorbents (activated vegetable charcoal);
tranquillizers, sedatives if indicated.
Essential to have very fresh samples for analysis as the compounds degrade rapidly.