primidone
Primidone is an anticonvulsant in the barbiturate class. It is used to treat focal seizures and generalized tonic-clonic seizures, as monotherapy or adjunctive therapy, though it is less commonly used today due to newer agents. It remains in use in certain regimens, particularly in patients who respond well or who have specific metabolic considerations.
Primidone is a prodrug rapidly absorbed from the gut and metabolized in the liver to two active
Mechanism of action: The anticonvulsant effects primarily arise from phenobarbital, which enhances GABA-A receptor–mediated inhibition.
Pharmacokinetics: Primidone undergoes hepatic metabolism with active metabolites that have longer half-lives. The phenobarbital metabolite can
Adverse effects: Sedation, dizziness, ataxia, and cognitive slowing are common, especially during initiation. Nausea, skin rash,
Interactions: As an inducer of hepatic enzymes, primidone can lower levels of other drugs such as other
History and status: Introduced in the mid-20th century as one of the early broad-spectrum anticonvulsants, primidone