Update on the Pharmacological Treatment of Chronic Migraine.

Chronic migraine (CM) is a common and disabling disorder that remains underdiagnosed and poorly treated. Significant unmet therapeutic needs add to the burden of this disorder; even when CM is recognized, effective treatment options are limited and randomized controlled trials supporting the use of various preventive medications are sparse. In this review, we discuss the available options for CM treatment. Currently the only FDA-approved treatment for CM prevention is onabotulinumtoxinA. Two double-blind studies have demonstrated the efficacy of topiramate for CM prevention, but it is not FDA-approved for this indication. Treatments in development for migraine will also be reviewed. Advancements in the understanding of migraine pathogenesis have identified new targets for both acute and preventive treatment and have engendered the development of targeted and mechanism-based therapies. The need for more effective treatment for CM patients, which has long since been identified, is now being addressed. Several of the emerging treatments for migraine prevention are under investigation specifically for CM or high-frequency episodic migraine.