Horse Wormer Dangerous to Pets

Beware of dogs and cats ingesting equine dewormers.


Please be aware that dogs and cats should not be present when you are deworming your horses.  We had a client call this week to tell us that their little Yorkie dog spent the weekend at the small animal emergency clinic being treated for a toxic exposure to Quest (moxidectin).   A small drop of the gel was licked up by the dog before they could stop her, and within minutes she was obviously very ill.  They rushed her to the emergency clinic and due to their prompt action she has recovered and is home now.

Moxidectin, the active ingredient in Quest, and ivermectin, the active ingredient in many brand name equine dewormers can be very toxic to dogs and cats.   The equine products contain levels of these compounds that are unsafe for small animals.  It only takes a very small amount to be toxic to small animals.

The signs of toxic exposure are drooling, dilated pupils, incoordination, and trembling which progresses to seizures, coma and eventually death unless the condition receives prompt treatment.

When deworming your horses please keep your dogs and cats in the house and make sure the empty syringes are securely disposed of.  If your dog is fond of eating horse poop keep them out of the paddocks and pastures for several days.  It is even possible for dogs to ingest toxic amounts by eating the manure of recently dewormed horses, although this is extremely rare.