Side Effects Of Phenobarbitol On Dogs

Phenobarbital often causes drowsiness in dogs.
Image by, courtesy of Faith Goble

"Phenobarbitol" is a common misspelling of the drug "phenobarbital." Phenobarbital is often prescribed for dogs with chronic seizure conditions, such as epilepsy, or for seizures brought on by poisoning or overdose of other medications. Side effects in dogs from phenobarbital are common.

Usual Side Effects

Common side effects of phenobarbital in dogs include drowsiness, agitation, increased appetite, increased thirst and increased urination.

Time Frame

According to veterinarian Dr. Mike Richards, the common side effects of phenobarbital in dogs should disappear in three to four weeks, once the dog's body has adjusted to the medication. If the dog has not adjusted, call your vet promptly.


Long Term

According to Mike Richards, DVM, and Dr. Dawn Ruben, long-term side effects of phenobarbital include kidney or liver damage.



In order to prevent long-term side effects from phenobarbital in dogs, Dr. Richards recommends regular blood tests to check liver and kidney functions.



According to The Pill Book Guide to Medication for Your Dog and Cat, symptoms of phenobarbital overdose in dogs include vomiting, strange and uncontrolled movements of the eyes, yellowing of the gums and coma.