The serum half-life of valproic acid is typically in the range of 6 to 16 hours. Half-lives in the lower part of the above range are usually found in patients taking other antiepileptic drugs. A slight delay in absorption occurs when the drug is administered with meals but this does not affect the total absorption. As sole or adjunctive therapy in the treatment of simple or complex absence seizures, including petit mal, and is useful in primary generalized seizures with tonic-clonic manifestations. Valproic acid may also be used adjunctively in patients with multiple seizure types which include either absence or tonic-clonic seizures.
Complex absence is the term used when other signs are also present.
Contraindications Patients with hepatic disease or significant dysfunction. Hypersensitivity to valproic acid. The most commonly reported adverse reactions are nausea, vomiting and indigestion. Since valproic acid has usually been used with other antiepileptics, in most cases it is not possible to determine whether the adverse reactions mentioned are due to valproic acid alone or to the combination of drugs. Nausea, vomiting and indigestion are the most commonly reported side effects at the initiation of therapy.