My cat is shaking and lethargic after deworming. Is it serious?

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.

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.

Hi Joanna, you really need to get a second opinion from another vert. It sounds like a hypersensitivity reaction to the topical deworming treatment. He needs an injection of an anti-inflammatory/steroid and anti-histamine and some fluids to counteract the reaction. He should feel better pretty quickly after that treatment.

It sounds like he is pretty sick. He may need more than just a deworming, such as fluids and possibly some anti nausea medication. I would really taking the worm in a baggie with you when you take Daknto the veterinarian. If he seems weak and lethargic then you may want to go to an emergency clinic tonight. Best of luck and thank you for using Pet Coach.

Thank you for visiting Petco Pet Education Center, formerly Petcoach. What you describe definitely sounds like tapeworms. I am sorry to hear that Toby sounds like he is having an adverse reaction to the tapeworm medicaiton. This sounds serious. I would highly recommend taking Toby in to your vet to have him treated for an adverse reaction, which includes fluids for flush out his system and and symptomatic treatment. It’s best to take him in right away if possible. I hope that your pet Toby is able to make a full and speedy recovery. Best wishes and take care.

Some kittens will become lethargic if there is a high worm burden in their intestines. The sudden death of a large number of worms can slow things down in their GI tract and cause discomfort. If she goes longer than 24 hours without food, or is seen having vomiting or diarrhea, then Tessa should be re-evaluated by your vet.

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.