Valproic acid is used primarily for which condition?

Valproic acid is primarily used for seizure control, making it a critical medication in the management of epilepsy and other seizure disorders. It functions as an anticonvulsant by increasing the availability of gamma-aminobutyric acid (GABA) in the brain, which helps to stabilize electrical activity in the neurons and reduce the frequency and severity of seizures.

In contrast, the other conditions listed are not effectively treated with valproic acid. Hypertension is typically managed with antihypertensive medications, while pain relief often requires analgesics or anti-inflammatory drugs, and heart rhythm regulation is achieved through antiarrhythmic medications. Thus, valproic acid's specific action in modulating neuronal excitability directly correlates its primary use in seizure control.