From the FDA Drug Label
Concomitant antiepilepsy drug (AED) dosage can ordinarily be reduced by approximately 25% every 2 weeks. The speed and duration of withdrawal of the concomitant AED can be highly variable, and patients should be monitored closely during this period for increased seizure frequency.
To taper valproic acid, reduce the dosage by 25% every 2 weeks while monitoring the patient closely for increased seizure frequency, as the speed and duration of withdrawal can be highly variable 1.
From the Research
Tapering valproic acid should be done gradually over 2-4 weeks to minimize the risk of seizure recurrence or withdrawal symptoms. Begin by reducing the daily dose by 250-500 mg per week, depending on the patient's current dose and clinical situation, as supported by the general principles of antiepileptic drug tapering 2. For example, if a patient is taking 1500 mg daily, reduce to 1250 mg daily for one week, then 1000 mg daily the following week, and so on until discontinuation. Patients on higher doses or those who have been on valproic acid for longer periods may require a slower taper.
During the tapering process, monitor for breakthrough seizures, mood changes, or withdrawal symptoms such as anxiety, insomnia, or irritability. If these occur, slow the taper rate. For patients transitioning to another antiepileptic medication, the new medication should be titrated to therapeutic levels before beginning the valproic acid taper, considering the pharmacokinetic interactions between valproic acid and other antiepileptic drugs 3, 4. Abrupt discontinuation of valproic acid can precipitate seizures even in patients without epilepsy and may cause status epilepticus in those with seizure disorders, which is why a gradual taper is essential. Patients with bipolar disorder should be monitored for mood destabilization during the taper process.
Some key considerations in the tapering process include the patient's specific seizure type and history, as well as potential interactions with other medications, highlighting the importance of individualized care 5, 6. The choice of replacement medication, if any, should be guided by the most recent and highest quality evidence available, such as the comparative efficacy of antiepileptic drugs for generalized epileptic seizures 2.