Epilepsy
How it works
Valproic acid, supplied as the sodium salt valproate semi sodium, is a fatty acid with anticonvulsant properties used in the treatment of epilepsy. The mechanisms of its therapeutic actions are not well understood. It may act by increasing gamma-aminobutyric acid levels in the brain or by altering the properties of voltage dependent sodium channels
Valproic Acid dissociates to the valproate ion in the gastrointestinal tract and then binds to and inhibits GABA transaminase. The drug’s anticonvulsant activity may be related to increased brain concentrations of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the CNS, by inhibiting enzymes that catabolize GABA or block the reuptake of GABA into glia and nerve endings. Valproic Acid may also work by suppressing repetitive neuronal firing through inhibition of voltage-sensitive sodium channels. It is also a histone deacetylase inhibitor.
Indications
Epilepsy
Dosage
200 mg TID, 300 mg BID, 500 mg/ day in two divided doses, Increase by 200mg/day at 3 day intervals
Side Effects
Headache, nausea, vomiting, diarrhoea, anorexia, increased appetite, wt gain, nystagmus, somnolence, dizziness, fatigue, hyperammonaemic encephalopathy, hypothermia, hallucinations. Thrombocytopenia (dose related), tremors, LFT elevation. Chronic use may lead to carnitine deficiency
Contraindication
Preexisting or family history of hepatic dysfunction, active liver disease, porphyria; mitochondrial and urea cycle disorders. Hepatic impairment. Pregnancy