Antiepileptic medications or anticonvulsants are drugs that treat seizures (epilepsy). Two also help to prevent migraine: topiramate (or Topamax), valproic acid (or Depakote). Both of these drugs have been proven effective for some patients and are approved for use in the management of migraine.
It is not known how these medications prevent migraine attacks, but they affect several targets in the brain. Their action at those targets appears to calm the overexcited nerves. Overexcited nerves play a role in migraine. Researchers aren’t certain how this process works to prevent migraine attacks (or seizures, for that matter), but it does so safely and effectively for most patients.
Based on research comparing the effectiveness of 100 mg vs. 200 mg per day of Topamax, the target dose for most people is 100 mg (50 mg taken twice a day). A higher dose has not been shown to work better at preventing migraines, although the dosage range recommended is 25 mg to 200 mg per day.
If your doctor prescribes this medication for you, they will start you on a relatively low dose—25 mg once a day for a week, for example—and then increase your dose by 25 mg per week until you’re taking your target dose. This is referred to as ‘titration’ and is very important to allow your brain to adjust to the medicine.
Likewise, if you’ve been taking these medications and would like to quit, it’s advisable to first consult with your doctor, who will guide you through tapering down your dose—again, to lower the risk of side effects that can occur if you stop cold turkey.
Both topiramate and Depakote have been shown to cause a host of side effects. Most are mild to moderate in severity and temporary; as your body gets used to the medication, any initial side effects are likely to disappear. Call your doctor if they don’t.
Pregnant women must not take these medications as they have been shown to cause birth defects. And you should not drink alcohol while taking these medications.
It usually takes at least 8 weeks to see a benefit from these medications. Around 45% of patients will see a 50% reduction in migraine attack frequency, meaning a majority will not gain a benefit, so it is best not to expect great things.
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