Topiramate for migraine prevention: an update.

Although the drug topiramate initially was developed for the treatment of epilepsy and received its first US Food and Drug Administration (FDA) approval for that purpose, it subsequently was shown to be effective for the prevention of migraine headaches and is FDA approved for that indication as well. Migraine and epilepsy share a considerable number of biologic and clinical features, and it follows that certain of the newer anti-epileptic drugs are effective for the prevention of migraine attacks as well as seizures. Precisely how topiramate prevents migraine is unclear, but generally speaking, it appears to reduce the genetically derived brain hyperexcitability that provokes migraine attacks in susceptible individuals. While the clinical trials for migraine prevention that earned topiramate its FDA approval involved patients with episodic migraine (ie, less than 15 headache days per month), 1 large, randomized, placebo-controlled study indicated that topiramate may be effective for patients with chronic migraine as well (ie, 15 or more headache days per month). In a head-to-head study, patients with chronic migraine responded equally well to topiramate vs onabotulinumtoxin A injection therapy . . . but generally preferred the latter due to its more favorable side effect profile. At this point, onabotulinumtoxin A is the only therapy specifically approved by the FDA for the treatment of chronic migraine. As a potent “brain active” medication, topiramate is not without potential side effects. Early in therapy, topiramate may cause nausea or other gastrointestinal distress. It also commonly produces an odd “pins and needles” sensation that may involve the hands, feet, or even the face; this side effect is benign, causes no neurologic injury, typically occurs early in the course of therapy, and is usually transient. More concerning is the drug’s potential for causing behavioral or cognitive disturbance, the latter typically manifested by impaired recent memory, impaired concentration, or word-finding difficulties. While these cognitive side effects occur in a minority of patients and may be minimized by beginning with a low dose and gradually increasing the dosage each week, the “start low/go slow” technique does not totally eliminate the chance of their occurrence. In rare instances, during the first 1 to 2 months of treatment, the drug may cause impaired vision by increasing intraocular pressure (“glaucoma”), and if you experience an unexpected disturbance of vision after beginning topiramate, you should stop the drug immediately and call your health care provider (HCP). Topiramate not uncommonly causes weight loss, and the degree of weight reduction tends to correlate with the drug’s dose, the duration of therapy, and the individual’s baseline weight. Headache © 2012 American Headache Society Published by John Wiley & Sons, Inc. doi: 10.1111/j.1526-4610.2012.02161.x