My cat isn't eating after worm medicine. Is this a normal side effect?

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.

It is quite possible that he is nauseous from the medicine or he had a lot of worms which are now dying and that is causing him a tummy ache. Don;t feed him for 12 to 24 hours and then offer him some bland food such as boiled white rice and boiled white boneless chicken. Feed him small portions often. When he has regained his appetite he should be fine. There is a possibility that he will get diarrhea as well for a day or two as the body is going to try to get rid of the worms as quickly as possible.

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.

Poor Frodo! Some cats do vomit during deworming due to the strength of the medication combined with the parasites moving through the GI system. These side effects should only last a few days, so if it's been longer than that, I would be concerned that it could be due to something else, such as a GI illness, a foreign body, or pancreatitis. I recommend withholding food for 12 hours, then feeding a bland diet of boiled white meat chicken (no bones) in small amounts several times a day for a couple of days. Then slowly add back in his normal diet. If the vomiting continues in the absence of food, he vomits the bland diet, develops diarrhea, stops drinking water, starts vomiting water, or becomes very lethargic, he will need to see a vet right away.

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Laila. I would advise taking her to your vet immediately if she won't eat. She may be running a fever, have some pain/discomfort, etc. Your vet can take a detailed history, perform an examination, and recommend a diagnostic/treatment plan. Once a diagnosis is made a sound treatment plan can be implemented. You can try cyproheptadine if you have it but I'm concerned she may be running a fever from a viral infection, not sure how much the cypro will help. The normal dose is 2 mg every 12 hours in cats. Good luck

If Gizmo hasn't eaten in 3 or more days, she is at risk of developing serious liver related complications. At this point in time, she needs to be examined by your veterinarian. Blood work should be submitted to assess major organ function. Bring the medication your gave her (or the package it came in) to your vet for examination as well. She may require hospitalization and supportive care until she is eating on her own. Discuss payment plans with your vet as well as alternative financing options such as Care Credit (www.carecredit.com). You may also seek financial assistance through Red Rover (www.redrover.org).

Thank you for submitting your question regarding your kitten. If he is not improving, then I recommend that he has a further work up. He should have fecal testing, blood work and x-rays of his abdomen to determine the cause of his vomiting and inappetance. Kittens can react to deworming medication, but it is typically a short lived reaction. It worries me that he is still ill. There is likely another another disease process present. In the meantime, encourage him to drink so that he does not become dehydrated. I hope this information helps!