Question

Valproic acid

Answer 1

Valproic acid: It is also called as sodium valproate.

Valproic acid is branched chain aliphatic carboxylic acid that has a broad spectrum anticonvulsant action. It act through multiple mechanisms:

• A phenytoin like frequency dependent prolongation of Na+ channel inactivation.
• Weak attenuation of Calcium mediated T current.
• Augmentation of release of inhibitory transmitter GABA by inhibiting its degradation by GABA transaminase and increasing its synthesis from glutamic acid.

It is well absorbed orally and highly bound to plasma proteins. It is completely metabolized in liver and excreted in urine. Its plasma t1/2 is 12-15 hours.

Adverse effect: anorexia, heart burn, vomiting, drowsiness, tremor, ataxia are common and dose related. Alopecia, curling of hairs, increased bleeding tendency, rashes and thrombocytopenia have been observed.

Dose: Starting dose for adult is 200 mg TDS and can be increased to maximum 800 mg TDS. Children dose is 15-30 mg/kg/day.

Uses: It is drug of choice for absence seizures and an alternative for General tonic clonic seizures, Simple partial seizures and Complex partial seizures.

Valproic acid has some prophylactic efficacy i migraine.