Primidone is used to control seizures in dogs. It is believed that Primidone alters the chemical impulses in the brain that cause seizures. Primidone is a prescription medication available as 250mg scored tablets. The usual dose in dogs is 2.3-6.8 mg/pound per day in 2 or 3 divided doses. Primidone may be also be used for purposes other than those listed in this guide.