My dog's phenobarbital side effects are worsening. What's happening?
Updated On September 23rd, 2025
Pet's info: Dog | Labrador Retriever | Male | neutered | 75 lbs
8 yr lab started phenobarbital 15 days ago. The effects of the drug appeared to be subsiding. Wobbly hind end, falling over on hind end. The last couple days they have seemed to get worse. He is dazed, panting, drooling, and still continues to fall over. on metacam as he does have arthritis in his hips. Is this still a reaction to the medication and the arthritis or am I looking at something more sinister. We have blood work on the 27th. Has had seizures since age of 3 just started more recently
2 Answers
Most Helpful Answer
Published on July 18th, 2018
Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. In the initial stages of starting Phenobarbital, dogs develop what we call transient symptoms. These include becoming wobbly (ataxia), drooling, disorientation, panting, etc. These symptoms will eventually subside as the dog's body becomes used to the phenobarbital. If Trapper is no longer having seizures, I would call the veterinarian and ask if the dose can be slightly lowered. I hope this helps! Please let me know if you have any other questions or concerns and I would be more than happy to help you further.
1Pet Parents found this answer helpful
Related Answers from Veterinarians
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Published on March 18th, 2020
Hello. Typically, phenobarbital takes a bit of time to get used to. The average amount of time to see some effects is 4-6 weeks, but every animal is an individual case, so it can vary. Expected side effects would be drowsiness, excessive drinking and sometimes excessive hunger. If your pet is so drowsy that they cannot walk , eat or function relatively normally - I would suggest that you speak with your veterinarian about adjusting the dose. It can elevate liver enzymes. Usually, blood is drawn periodically to check the therapeutic levels. This helps determine dosage adjustments. If your pet has months in a row without a seizure, you may want to ask about lowering the dose. We try to achieve the lowest dose that is effective at controlling the seizure activity. Thank you for using Petco Pet Education Center, formerly Petcoach
1Pet Parents found this answer helpful
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