Retrospective Evaluation of Factors Associated with the Morbidity and Outcome of Permethrin Toxicosis in Cats

Cats exposed to permethrins, which are present in ectoparasite control products intended for dogs, may develop signs of toxicity. This retrospective study describes the clinical course of permethrin toxicosis in cats, and examines if methocarbamol treatment had improved its morbidity and outcome. The study included 61cats diagnosed with permethrin toxicosis presented to the Hebrew University Veterinary Teaching Hospital. In most cases (89%), the owners have inadvertently applied anti-flea spot-on products designated for dogs to their cats, resulting in toxicosis-related clinical signs. These most common signs included tremors and twitching (90%), hypothermia (39%), seizures (30%), tachypnea (25%), abnormal mentation (18%), ataxia (16%), ptyalism (11%) and mydriasis (10%). Treatments included whole body bathing (85%), along with supportive care, sedatives and muscle relaxants. Some cats (5%) required general anesthesia. The median hospitalization period was one day (range, 1-9). The survival rate was 100%. Methocarbamol (50-330 mg/kg, slow IV PRN) was administered to 41 cats (67%), which had a shorter (P=0.032) hospitalization period (median, 1 day) compared to that of cats untreated with methocarbamol (2 days). Cats with seizures treated with methocarbamol had a shorter (P=0.08) hospitalization period compared to that of cats untreated with methocarbamoL In conclusion, permethrin toxicosis occurs in cats, mainly by inadvertent application of canine flea insecticide spot-ons. The overall prognosis of such cases, when treated intensively was excellent. Herein, methocarbamol treatment of cats with this toxicosis, in general, as well as particularly in those presenting seizures, decreased their morbidity, as reflected by a shorter hospitalization period.