Why is my kitten lethargic after Nemex dewormer for roundworms?

A side effect of the deworming treatment can be lethargy, which would be due to the vomiting and the movement of dead worms through Leo's intestinal system. This should pass in another 24 hours, but if it doesn't, I would have him seen by a vet for a heath check.

I am concerned as well. While a kitten can have some lethargy after receiving vaccines and deworming treatments, it's not normal for that to last more than a day or two. If she is eating and drinking normally, then you can wait until the morning to have her seen by a vet by a health check. Should she not be eating or drinking normally, then I would have her seen by an ER vet tonight.

He needs to be seen by a veterinarian for a wellness exam. He may not be able to poop and may be constipated, or he had so many worms that all the dead worms are making him ill. Keep him warm, entice him to drink water, and should he deteriorate he needs to be seen at a petER tonight.

Some loss of appetite/lethargy can be normal after a deworming, especially if there was a heavy worm load that is now dying off. You can try to entice eating by offering some plain boiled chicken or wet food warmed up as cat's appetites are driven by smell. However, if it's been several days and Layla still isn't back to normal, isn't eating or drinking at all, or is very lethargic, it is best to let your vet know to make sure there isn't another underlying issue that needs to be addressed.

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! I have seen deworming pills cause an upset tummy: vomit, diarrhea, decreased appetite. It usually resolves in 1-2 days. The pill may not be the cause of why Lucy isn't acting normal. If it has been 2 days since you gave the pill I would have Lucy seen by your Vet to make sure she is ok. I hope this helps and I wish Lucy the best!

Thanks for using Petco Pet Education Center, formerly Petcoach! Without seeing the cats, it is hard to say. I recommend taking them to the vet with a fresh stool sample to rule out other parasites. Not all deworming medications treat all intestinal parasites. If negative, I would have both cats tested for feline leukemia and FIV. These are infectious diseases that could cause poor growth. Good luck and kisses to the kittens!

Poor Kai! I'm sorry to hear that he isn't feeling well and I understand your concern! In some puppies with a significant burden of roundworms, vomiting and diarrhea can occur as a means of expelling the worms. This also can cause inappetence from nausea and mild lethargy as a result. Although rare, intussusception (essentially intestines that telescope into one another) can occur in cases of parasitism, which can cause vomiting, lethargy and inappetence. At this point, monitor Kai for changes tonight and try to tempt him to eat with boiled white meat chicken and white rice as a bland diet. If he is still lethargic and not eating by the morning, he should be examined by his vet. The greatest likelihood is simply that his body is working to expel the roundworms.