Botulinum toxin A (Botox) injections can help prevent migraines in patients who have headaches almost every day, according to a new report.

“Our study focused on migraine patients with chronic daily headache, which is defined as having a headache at least 15 days per month,” said lead author Dr. David W. Dodick, from the Mayo Clinic in Scottsdale, Arizona. “These patients represent a minority of all migraine sufferers, but they account for at least 50 percent of the patients seen in specialty headache clinics.”

“This is an important group to look at because they are often excluded from migraine studies and because there’re no approved therapies for chronic daily headache,” Dodick explained. “There is a desperate unmet need for agents targeting this group of patients.”

The idea of using Botox as a preventative agent for migraines came in 1992 when a Los Angeles plastic surgeon noticed fewer headaches in a patient who was being treated with the agent for its skin-smoothing effects. Since then, several studies have evaluated botulinum toxin as a migraine preventative.

In the present study, 228 patients with chronic daily headaches were randomly allocated to botulinum toxin injections or inactive “placebo” injections of saline every 3 months for 11 months.

Dodick said that the injections are placed primarily in the area of the trigeminal nerve, but may continue into other areas as needed to “follow the pain.” In the current study group, the number of injections during each treatment session ranged from 10 to 25 per patient.

Treatment with botulinum toxin reduced the frequency of migraine attacks per month from 14 to 6 - a reduction of 55 percent. By contrast, with placebo, attacks dropped from 12.9 to 8.4 per month, for a significantly lower reduction of 35 percent.

Dodick said that treatment with Botox “was also linked to a significant reduction in headache severity and with a drop in the use of acute headache medications.”

Botulinum toxin is not currently approved by the US Food and Drug Administration for use against migraines, Dodick noted. “This was an exploratory study. Now, we will embark on registration trials, which will determine whether the FDA approves this drug for migraines.”