Hello, my name is***** and I have over 20 years of experience as a veterinarian. I understand that you are concerned that your kitty ingested a Heartgard Plus pill containing 68mcg of ivermectin and 57mgs of Pyrantel.
Both of these medications are used in cats for worm
prevention and treatment.
ivermectin is a very safe medication that we routinely give doses daily several times higher then the dose in Heartgard to treat other types of parasites such as demodex mites. Cats take ivermectin for heartworm
prevention too, and they actually take more per pound of body weight than dogs do. A 7lb cat would take 165mcg, so he actually took a below normal dose. I would not expect this to be a problem for him.
Things to watch for with a toxic dose of ivermectin are drooling, vomiting, diarrhea
, incoordination and possibly seizures, sometimes blindness that does resolve in most cases in time.
But given the amount he ingested I think he will be fine and I don't expect that you will see any side effects.
Pyrantel is an intestinal parasite wormer. The usual dose is for a cat his size would be as high as 72.6mgs, so 57 mgs should not be a problem for him.
In short although this wasn't meant for your kitty, it should do him no harm.
Please let me know if you have any further questions.