Valentine WM
Pyrethrin and Pyrethroid Insecticides.

Vet Clin North Am Small Anim Pract, 20(2): 375-382, 1990
ISSN: 0195-5616 The Veterinary Clinics of North America - Small Animal Practice (pubmed.ncbi.nlm.nih.gov)

Abstract
Pyrethroids have a wide spectrum of insecticidal potency, vertebrate toxicity, and environmental stability. The exceptionally high selectivity ratios of pyrethrins and pyrethroids have resulted in their use for insect control in numerous formulations. A primary effect of pyrethroids is to slow the closing of the sodium activation gate in nerve cells. All pyrethroids have essentially the same basic mechanism of action on voltage-dependent sodium channels but differ in the magnitude of effect. Based on clinical signs, electrophysiologic responses, and chemical structure, pyrethroids can be classified as Type I or Type II. Inhibition of the GABAA receptor appears to be an additional mechanism of Type II pyrethroids. Clinical signs in small animals during a pyrethroid toxicosis vary but are generally attributable to neural dysfunction. Treatment consists of decontamination procedures and application of appropriate symptomatic care, including control of seizures if necessary.