Pesticide toxicity (Proceedings)


Pesticide toxicity (Proceedings)

Aug 01, 2010

Pesticides - Agents (physical, chemical or biological) designed to kill pests that interfere with the comfort, health or economic wellbeing of man. Accompanying their beneficial effects, illnesses and deaths in man and animal alike, have been reported. Recorded use of compounds in the control of pests goes back to 1000 BC, when sulfur was used for such purpose. Since then their have been continued development of more effective and safe pesticides. Currently in use today are > 600 pesticides, constituting 15,000 compounds in 3,500 formulations.

In this presentation, pesticides will be discussed as a group (Rodenticide, Insecticides) on the basis of the syndrome (acute and/or chronic), mode of action, toxicity, toxicokinetics, clinical signs, diagnosis, treatment and prognosis. Newer insecticides (Fipronil, imidacloprid, Serlamectin, Lufenuron, nitenpyram, their vehicles, and petroleum distillates) will be addressed as to their efficacy and low toxicity. When possible (time allowing) cases scenarios will be included.

Pesticides Classified by groups are Insecticides (the most common cause of small animal Poisonings), Herbicides, Fungicides, Rodenticides, and Neonicotinoids. Classified on the basis of production: Herbicides > Insecticides > Fungicides > Rodenticides > others.

Common clinical signs (present [+] or absent [-]) associated with rodenticide poisoning in companion animals
Rodenticides (anticoaguants (warfarin and second generation compounds) cholecalciferol, Bbomethalin, (strychnine, 1080, thallium, ANTU, zinc phosphide not currently widely used, to name a few) are the most common causes of animal poisoning, the majority attributable to anticoagulant baits. The relative incidence rates: Dogs > Cats

Toxicity of Common Anticoagulant Rodenticides
They share common mechanism of action and are classified as first or second generation, indicating their potency and ability to kill warfarin resistant rodents


They are 90% absorbed from the GI tract; 95% plasma protein bound; undergo Liver metabolism; and Renal excretion; Plasma T1/2 of 20-24h (dogs) – first generation; Plasma T1/2 of 6 ± 4 days – second generation


All animals including birds are susceptible. Concurrent administration of other compounds (aspirin, phenylbutazone) which are also highly protein bound, increase tocicity. Relay toxicity – moderate to high with second generation anticoagulants.