Q. Our dog was put on phenobarbitol to control his seizures. What are the side effects of this medication?
A. Side effects may include sedation, lethargy, excessive thirst/urination/hunger, hyperexcitability, ataxia and restlessness.Â Â Most of these will lessen after several weeks of therapy. The most common lingering side effects are excessive thirst/urination and an increased appetite. Monitoring is critical to confirm therapeutic levels as well as to diagnosis potential liver complications early.