Clinical effects and outcome of feline permethrin spot-on poisonings reported to the Veterinary Poisons Information Service (VPIS), London

J Feline Med Surg. 2007 Aug;9(4):335-9. doi: 10.1016/j.jfms.2007.05.003. Epub 2007 Jul 12.


Permethrin is a pyrethroid insecticide used in dermally applied spot-on flea treatments for dogs. Permethrin-based spot-on preparations are contraindicated in cats because of the high risk of toxicosis. The Veterinary Poisons Information Service (VPIS) is a 24-h access telephone service that provides veterinary professionals in the United Kingdom with information on the management of poisoned animals. In a review of 286 cases reported to the VPIS regarding inappropriate feline exposure to permethrin spot-on (PSO) preparations, 96.9% were symptomatic. Increased muscular activity (as evidenced by twitching, tremor, muscle fasciculations or convulsions) was common and occurred in 87.8% of cases. The duration of increased muscle activity was long, with convulsions lasting on average 38.9 h and tremors 32 h. Recovery typically occurred within 2 to 3 days but in some cases took 5 to 7 days. Death occurred in 10.5% of cases.

MeSH terms

  • Animals
  • Cat Diseases / epidemiology*
  • Cat Diseases / etiology
  • Cat Diseases / pathology
  • Cats
  • Insecticides / poisoning*
  • London / epidemiology
  • Outcome Assessment, Health Care
  • Permethrin / poisoning*
  • Poison Control Centers / statistics & numerical data
  • Poisoning / epidemiology
  • Poisoning / veterinary
  • Severity of Illness Index
  • Surveys and Questionnaires


  • Insecticides
  • Permethrin