What is the mechanism of action for valproic acid?

Valproic acid primarily functions by enhancing the activity of gamma-aminobutyric acid (GABA), which is a key neurotransmitter in the central nervous system known for its inhibitory effects. By increasing GABA levels, valproic acid helps to stabilize neuronal membranes and reduce excitability, making it effective in the treatment of various conditions such as epilepsy and bipolar disorder.

While there are additional mechanisms that valproic acid may engage, such as affecting ion transport and potentially inhibiting enzymes involved in GABA metabolism, its most significant pharmacological action is the enhancement of GABA’s inhibitory action in the brain. This action is central to its therapeutic effects, especially in reducing seizure activity and mood stabilization.

Other mechanisms related to sodium and calcium channel blockade are also relevant to the action of valproic acid, but they are secondary to its role as a GABA modulator. Therefore, the ability of valproic acid to enhance GABA activity is the most distinguishing and clinically relevant aspect of its mechanism of action.