Has sodium valproate hypnotic effects?

Eight fasting normal subjects were given a single dose of sodium valproate, 400 mg, phenobarbital, 60 mg, or the two drugs in combination, in a double-blind placebo-controlled study. The effects were assessed behaviorally and by a standard 30-min EEG, begun 1 hr after the treatments had been given. The recording was rated for the amount of drowsiness and sleep, independent of which drug had been given. The scores obtained indicated that valproate intself has hypnotic action, and there is a tendency for this to be increased by the simultaneous administration of phenobarbital.