One in seven people worldwide experience migraines, among them 37 million Americans — as many as 20 percent of women, and 10 percent of men.

About 2 percent of the global population copes with chronic migraines. By some estimates, migraine is the third most common disease in the world, and it ranks among the top ten causes of disability.

It is not just a headache: A migraine often is accompanied by disabling symptoms like nausea and vomiting, difficulty speaking, and an aversion to light and noise. The headache can be throbbing and last for hours or days.

The new medicines are intended for the estimated 2.8 million Americans who have a migraine many times each month. Treating these people has been challenging, doctors say.

Patients often try the currently available treatments one after another, in varying combinations. Drug side effects are frequent and include mental fogginess, sedation, weight gain, sexual dysfunction and dry mouth leading to cavities.

Some patients find the side effects worse than the migraines. Eighty-five percent of migraine patients stop taking the drugs within a year.

For a draft review of migraine drugs, the nonprofit Institute for Clinical and Economic Review surveyed patients with frequent migraines. Many said they did not make plans or commitments — even staying out of the work force — because they never knew when they would get a migraine that could disable them for hours or days.