A review of valproate in psychiatric practice.

Valproate (2-propylpentanoate) is available as valproic acid, sodium valproate and semisodium valproate. It has actions on dopamine, GABA and glutamate neurotransmission and intracellular signaling. Its main psychiatric use is to treat bipolar disorder. It has been used in other psychiatric disorders, including schizophrenia and borderline personality disorder, but data are insufficient to recommend this. In acute mania, valproate monotherapy has similar efficacy to antipsychotic drugs and lithium whereas the combination of valproate and an antipsychotic is more effective than either drug alone. In maintenance treatment of bipolar disorder, valproate monotherapy has comparable efficacy to olanzapine although placebo-controlled evidence is limited. Maintenance treatment with valproate and quetiapine or olanzapine is more efficacious than valproate alone when an acute episode responds to the combination. Common adverse effects of valproate include weight gain, gastrointestinal symptoms, sedation, tremor and mild elevation of hepatic enzymes. Serious hepatic toxicity is rare in adults. Many adverse effects are dose related and resolve with dose reduction. Valproate is teratogenic and specifically associated with neural tube defect. Preliminary evidence has linked in utero exposure to decreased verbal intelligence in the offspring. These effects, plus a probable increased risk of polycystic ovary syndrome, limit valproate's use in women of childbearing potential.