What are the Side Effects of Prednisone and Prednisolone?


My cat has been taking predinsolone (5mg twice daily) for one week. She showed signs of aggression yesterday morning. She vomited and had much looser than normal bowel movements while I was at work. Last night she could barely move and would not eat, but I gave her the pill anyway because of possilbe side effects of not. This morning she was panting and we thought she might die. Had not eaten or drank any water and refused to do so. I did not give her the pill and stayed home with her. After several hours she began to eat and then drank water and is now acting normal. Do I have to give her another pill to keep her from having side effects worse than those she had from the medicine? She was diagnosed with asthma when I took her to the vet, but is definitely worse off now than she was then.

Thank you,


Your cat definitely sounds like she is suffering from side effects from prednisolone. You need to work with your vet to reduce her dosage and wean her off the medicine as soon as possible.

Prednisone and prednisolone are steroids related to cortisone. Prednisolone is the active drug; prednisone is converted to prednisolone in dogs’ bodies, but cats are not very efficient at the conversion. Therefore cats generally take only prednisolone. Both drugs are commonly known as “pred”.

Pred is a powerful medication used to treat a number of diseases mediated by the immune system, including feline asthma. Unfortunately, pred also can cause side effects. Initial side effects include increased thirst, increased hunger, aggression, panting, and lethargy. More severe reactions can include vomiting, diarrhea, dehydration, heart failure, diabetes, and severe infections from immune system compromise.

Animals that have been on pred for a while can’t suddenly stop taking the medicine. The medicine must be discontinued in a gradual fashion. If you suspect your pet is suffering side effects from pred or any medicine, call your veterinarian immediately.

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