Divalproex sodium (Depakote) is one of two epilepsy drugs that are also approved by the FDA for the preventive treatment of migraine headaches (the other one is topiramate, or Topamax). It was approved by the FDA in 1983 to treat epilepsy, in 1985 it was also approved to treat bipolar disorder, and in 1986, to treat migraines.
Divalproex is very effective in about 50% of migraine sufferers. The starting dose is 500 mg of the extended release form (Depakote ER). Some patients require 1,000 mg and in epilepsy patients, up to 2,000 and even more, depending on the blood level of the drug. Potential side effects include nausea, drowsiness, dizziness, hand tremor, and in about 10% of patients, weight gain and hair loss. These side effects can be quite unpleasant, but unfortunately, much more serious side effects can occur as well. These are rare, but when they occur, they can be devastating.
The drug carries a so called black box warning. It in includes hepatotoxicity, or liver damage, which can be fatal. It usually occurs during the first 6 months of treatment and the FDA label calls for monitoring patients closely and regularly performing blood tests. Fatal cases of pancreatitis have been also reported. Another major problem with this drug is birth defects if taken by the mother during pregnancy. Considering that the majority of migraine sufferers are women of child-bearing age and because of all other potential side effects I rarely prescribe divalproex.
It is appropriate to try divalproex after the patient fails to respond to a variety of other treatments, including blood pressure medications, antidepressants, Botox injections, and the new category of CGRP monoclonal antibodies (Aimovig, Ajovy, and Emgality). The patient must be informed of the potential side effects listed above and sexually active women of child-bearing age should be advised to use two methods of contraception.
