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Why is my dog so sleepy on prednisone and cephalexin for allergies?

Updated On September 23rd, 2025

Pet's info: Dog | Pit Bull Terrier | Male | neutered | 63 lbs

On Saturday, I took my dog to see our vet. He was prescribed two medications for allergies. The medications are called Prednisone and Cephalexin. After taking these medications, I have noticed that he has been super sleepy, slow and not very active. Should I be concerned?

1 Answer

Most Helpful Answer

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Answered By Jeffrey Milner

Veterinarian

Published on July 6th, 2017

Lethargy and altered behavior are pretty typical side effects of prednisone. Along with this you may also see things like increased drinking, urinating, and eating. Long term side effects can include liver damage and commencement of certain diseases of the endocrine system. Cephalexin is an antibiotic that has the main side effect of gastrointestinal upset. If you decide that you do not think the prednisone is worth using due to the side effects, do not discontinue it abruptly. It has to be tapered down slowly as to prevent any harm to Kaiser. Hope this helps.

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