Depakote® (valproic acid)
Valproic acid is available in many different forms. It is most commonly used in tablets known as Depakote®. More recently, it has become available in an extended release formulation to allow twice daily administration and this form is known as Depakote-ER®. The cost of this new form to achieve the same absorption is about 20% more expensive. Valproic acid is also available is a liquid form (Depakene®) and an IV form (Depacon®).
In the brain, valproic acid inhibits voltage sensitive sodium (Na+) channels. Valproic acid also increases brain GABA levels. GABA is an inhibitory neurotransmitter.Valproic acid is a broad-spectrum anti-epileptic drug (AED). This means it is active against both partial-onset and generalized-onset seizures. Another nice feature of this antiepileptic is that it does not interfere with the function of birth control pills.
Unfortunately, the medication can cause some serious side effects. Like all of the older AEDs, it has the potential to cause liver toxicity and birth defects. All women of childbearing age taking this medication should be taking extra folic acid to help prevent one of the most serious birth defects - neural tube defects (for example, spinal bifida). Women may become pregnant while taking this medication and should carefully discuss this in advance with their physician to minimize their own problems and their future child's problems during a pregnancy. Less commonly, valproic acid can cause pancreatitis and decreased platelet counts. Properly monitored in adults, it is a safe medication. Its most troublesome side effect is weight gain, which can be substantial.
Valproic Acid for Migraine Prevention and Acute Treatment
Valproic acid is one of the most effective medications for migraine prevention. The practice parameter guidelines published by the American Headache Consortium (endorsed by the American Academy of Neurology, among others), give this medication its highest rating. The dosing required for migraine prevention is relatively low compared to epilepsy and the hope is that it will therefore be less likely to cause weight gain. It is the experience of Dr. Loftus that, in general, those patients who gain weight on this medication will continue to do so year after year so the key is to recognize this side effect and change medications if it occurs.
If you are considering using depakote for migraine prevention, then you need to be tracking your headaches. Dr. Loftus has designed an iPhone or iPod touch app called iHeadache that does this.
More recently, the intravenous form of the medication, Depacon® is being used as an acute treatment for migraine. This is particularly useful for patients in whom a sumatriptan injection (Imitrex®) either does not work or is contraindicated.
Valproic acid is also a very useful medication for the treatment of cluster headaches.
Other uses of Valproic Acid
Valproic acid is also widely used by psychiatrists as a mood stabilizing medication. The details of its use in this area are beyond the scope of this web site.