Valproic acid is a drug that is used primarily to control certain seizures by lessening their severity and frequency. It may be prescribed in combination with other antiepileptic drugs such as phenytoin or phenobarbital. The valproic acid level in the blood must be maintained within a narrow therapeutic range.
The valproic acid test is used to measure and monitor the amount of valproic acid in the blood and determine whether the drug concentration is within the therapeutic range. The prescribed dose of the drug may be adjusted up or down depending on the results of the blood test.
The therapeutic range for total valproic acid (bound and unbound) has been established at 50-125 µg/mL and 6-22 µg/mL for free valproic acid (unbound only). The recommended range for the treatment of epilepsy is 50-100 µg/mL total valproic acid, while the recommended range for the treatment of acute mania is 85-125 µg/mL total valproic acid.
