Some of the treatments listed in the guidelines are FDA-approved to treat migraines. But many are approved for other conditions and used off-label in migraineurs.
"The fascinating thing about migraine prevention is almost all the therapies we have were developed for another purpose and discovered to work in migraine prevention by chance alone," said Lipton, describing how drugs designed for epilepsy and hypertension were found to work haphazardly in headache sufferers. "But I think we're moving into an era where we can develop designer drugs specifically for migraine."
The new guidelines are similar to those from 2000 with a few changes: Topiramate is now considered effective in migraine prevention; and gabapentin and verapamil were downgraded from "probably effective" to a category of treatments with "inadequate" evidence to support or refute its use. But experts emphasize the guidelines are not the be-all, end-all.
"They're useful as a starting point," said Saper, adding that difficult cases often required drugs not listed in general guidelines. "Many people respond well to drugs that don't help most other people, and those drugs don't get listed because there's not enough evidence of a generalized benefit."