(CNN) -- Federal health authorities on Friday approved Botox injections for the prevention of chronic migraines in adults, an advance experts described as "modest".
In a statement, the Food and Drug Administration recommended Botox be injected approximately every three months around the head and neck to dull future headache symptoms.
The drug -- whose generic name is onabotulinumtoxinA -- has not been shown to work against migraines that occur 14 days or fewer per month, nor has it been shown to work for other forms of headache, said the statement.
Experiencing a migraine on most days "is one of the most disabling forms of headache," said Dr. Russell Katz, of the Division of Neurology Products in the FDA's Center for Drug Evaluation and Research. "This condition can greatly affect family, work, and social life, so it is important to have a variety of effective treatment options available".
Migraines, an intense pulsing or throbbing pain in one area of the head, are often accompanied by nausea, vomiting and sensitivity to light and sound, doctors say. Chronic migraines are defined as those that occur on 15 days or more for more than four hours per day.
The drug, made by Allergan, Inc., of Irvine, California, was approved last month in Britain for the same purpose.
The two company-funded studies submitted to the FDA involved 1,384 adults from 122 study sites in Europe and North America. They found that after six months, patients who got the drug experienced 7.8 and 9.2 fewer days of migraine than they had before the studies started. Those who got injections of placebo (sugar pill) experienced 6.4 and 6.9 fewer headache days.
Over those six months, patients on the drug experienced 107 and 134 fewer hours of headache, versus a reduction of 70 and 95 hours for those on placebo, according to the studies.
CNN
