Valproic

Valproic acid, also known as valproate in its salt forms, is a branched short- to medium-chain fatty acid used as an anticonvulsant and mood stabilizer. Its chemical name is 2-propylpentanoic acid. It is marketed as valproic acid and as sodium valproate, valproate semisodium, and related salts, and is available in oral formulations and intravenous preparations.

Medical uses include the treatment of various seizure types in epilepsy (such as generalized tonic-clonic and focal seizures), maintenance therapy in bipolar disorder, and prophylaxis of migraines. It is also used off-label for other conditions, though efficacy and safety considerations vary by indication and patient.

Mechanism of action is multifaceted. Valproic acid increases brain gamma-aminobutyric acid (GABA) levels by inhibiting GABA degradation, and it modulates neuronal excitability through effects on voltage-gated sodium channels and T-type calcium channels. These actions contribute to its anticonvulsant and mood-stabilizing properties, though the exact mechanisms may differ among indications.

Pharmacokinetics and administration: Valproic acid is well absorbed after oral administration and reaches peak plasma levels within a few hours. It is highly protein-bound and extensively metabolized in the liver through glucuronidation and beta-oxidation, with excretion primarily in the urine. The drug can interact with other medications due to its effect on hepatic enzymes.

Safety and adverse effects: Common adverse effects include nausea, vomiting, weight gain, tremor, and alopecia. Serious risks include hepatotoxicity, pancreatitis, and thrombocytopenia. It carries a well-established teratogenic risk, notably neural tube defects, and is generally avoided during pregnancy unless no alternatives exist. Liver function tests and blood counts are typically monitored, and dosing is individualized.

Interactions and monitoring: Valproic acid is a hepatic enzyme inhibitor and can raise levels of other drugs (for example lamotrigine). Careful assessment of drug interactions, patient history, and ongoing monitoring are essential to minimize risk.