Warning: Do not use Hartz Drops for Cats on kittens less than 12 weeks old..
Case report of toxicity in a kitten. A 14 week old kitten was presented with acute seizures and tremors. Diazepam a commonly used emergency seizure medication was subsequently administered to no effect. The kitten was ultimately treated with methocarbamol and phenobarbitol. Two days after the incident the kitten was reportedly close to normal. It was later discovered that two days prior to the incident, the owner had applied Hartz Drops for Cats which is described as “a monthly treatment that kills fleas, deer ticks and mosquitoes and kills flea eggs for up to 30 days. This formula stops the flea life cycle and prevents re-infestation for up to 30 days. Do not use on kittens less than 12 weeks old.”
A Veterinary Information Network search revealed similar incidences in the US, that is tremors and seizures two days after exposure, which was successfully treated with methocarbamol and phenobarbitol, but not with diazepam. This report is provided for the information of veterinarians in Alberta that may encounter a similar presentation of this toxicity.