Why is my new kitten lethargic, twitching after dewormer and shots?

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.

It is possible that the worms were the reason why he wasn't eating, and the deworming treatment itself can make him feel nauseous and unwell. It's the result of the dead worms moving through his GI system. I would recommend offering him a bland diet of boiled white meat chicken (no bones) in small amounts to try to tempt him to eat. You can also soak his dry food in tuna juice, or offer him gently warmed really smelly wet food, such as sardine or fish based. If he still isn't eating in the morning, I would have him seen by the vet again. It will take at least two deworming treatments to kill all the worms.

This is very common after vaccines. Let him be alone tonight and let him rest. I would not be concerned unless he starts vomiting, having diarrhea, has hives or a swollen face. If any of these symptoms are noticed that I would contact your vet as this is likely a vaccine reaction. Also make sure he is still eating. He may not eat tonight but his appetite should pick up by tomorrow. If he isn't starting to act more normal in the next day or two, contact your vet for an exam.

Tater is adorable! The signs you are describing can be due to a reaction to a flea/tick preventative or a number of toxins in the environment. It is definitely concerning that Tater is also having diarrhea and loss of appetite/energy as this can be caused by viral and parasitic infections. I recommend having Tater seen by a vet as soon as possible to determine what is going on and begin the appropriate treatment. Your vet will likely recommend a fecal exam and blood work. I hope this helps and that all is well with Tater!

Kittens are susceptible to many different infections, both viral & bacterial. A heavy parasite burden from coccidia, or roundworms can also wear a kitten down & leave it weak. Pascal is too young & small to try & fight this off on his own. He needs to be seen by a veterinarian as soon as possible. If you can not have him seen tonight or tomorrow, pick up some Nutrical from Petco tomorrow, & try to give him small amount frequently throughout the day. This is a high calorie supplement to hopefully keep his energy up. Then please try to have him seen by your veterinarian as early as possible on Monday. I hope he does better soon. Thank you for using Petco Pet Education Center, formerly Petcoach.

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.

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.