Objective: To review the role of intravenous valproate (i.v. VPA) as an alternative to the oral route in the acute treatment of epileptic seizures and status epilepticus, and to establish criteria for its use.
Development: The bioavailability and tolerance of i.v. VPA, when administered in infusion for 60 minutes every 6 hours, are similar to those of oral VPA. Much of the data on acute administration, by injections of 3 to 5 minutes, for the treatment of seizures, are from series of cases and summaries from congresses and require confirmation. However, they suggest that i.v. VPA may be useful for the treatment of: a) convulsions due to insufficient blood drug levels or failure to take the drug, in order to rapidly raise the drug levels; b) a generalized convulsive status which is partially resistant to diazepam and phenytoin, as a non-depressant alternative to phenobarbital and other CNS depressants, and c) a non-convulsive status as an alternative to benzodiazepines when it is desired to avoid their side effects or when the treatment is going to be continued with oral VPA. The initial dose should be based on the concentration to be reached and the patient's previous VPA levels; the maintenance dose should be based on the stable level to be maintained, the age of the patient and the presence of enzyme inducers.
Conclusion: Intravenous VPA would seem to offer new perspectives for the acute treatment of seizures, but its usefulness may be critically dependent on its correct use based on clinical and pharmacokinetic principles.