Vet trouble for vet's pet

It's not only our clients' pets that get into mischief, sometimes our pets get into trouble too!


Dr Chantelle's little kitty got himself into a real wormy situation recently. Louis is a 2-year-old mischievous domestic long hair cat who already broke his wrist as a kitten. As it turns out, Louis also loves the taste of dog worming treatment, Drontal chews. 

One morning Louis jumped onto the kitchen bench sniffing out some doggy Drontal set aside for his furry cousins. The fact that they were in a plastic zip-lock bag did not deter him; he started to gnaw through the two layers of plastic and foil! Hearing the rustle of the bag, his owner took the chews off him and placed them in a drawer – out of sight, out of mind. Or so she thought!

Louis then retrieved the chews from the drawer while his mum was out to coffee. On her return, Louis had torn the bag apart and bit through the foil to eat two doggy chews (approximately a dose equivalent for a 20kg dog) and was in the process of eating more. Louis' mum rushed him into work and immediately made him vomit. Some of the granules came up but some of it had already absorbed into his system.

So why is this an issue?

Dog and cat flea and worming treatments are marketed as such for a reason. Dogs and cats have different metabolisms and drug pathways in their bodies, so they have different doses per kilogram of most medications. In this instance, Febantel, an active ingredient in the allwormer Drontal, is absent from the cat equivalent because cats are much more sensitive. It turns out Louis had overdosed approximately 4-5 times over the safe dose. We were very lucky that Louis had not got into dog flea treatment – that can cause seizures and possible death in cats.

The effects of Febantel toxicity in the cat are not very well documented. Dog and cat wormers are not frequently mistaken, and when they are, it is usually with an appropriate dose per kilogram causing no visible harm (however, repeat dosing even at low levels has been shown to be harmful). But Louis had markedly overdosed and after an hour or two became lethargic, ataxic (wobbly in his legs) and vomited a couple of times as the Febantel became effective in his system. He was closely monitored throughout the afternoon and evening and given anti-nausea medication. By about 11pm he had returned to having full function of his legs and was bright again.

The next morning he was back to his usual tricks and eating well. A full blood panel showed no lasting damage and everyone breathed a huge sigh of relief. It just goes to show that things can happen to our pets too!