Contrary to earlier reports, injections of botulinum toxin A - better known as Botox - do not seem to prevent migraine headaches occurring, according to results of a small study.

Two or three studies over the past couple of years have indicated that Botox helps migraine sufferers, although the best placement of the injections has been unclear.

In the latest study, Dr. Stefan Evers and colleagues from the University of Munster, Germany, examined the efficacy of Botox for the treatment of migraine with a specific focus on different injection sites.

The team treated 60 migraine patients with either high or low doses of Botox or an inactive placebo injected into muscle groups of the forehead and/or neck. The participants were followed for three months.

Over that period, migraine frequency was halved in 30 percent of the two Botox groups, compared with 25 percent of those given placebo injection, the investigators report in the headache journal Cephalalgia.

Overall, no significant differences were seen among the three groups in the reduction of migraine frequency, the number of days with migraine, or the amount of drugs needed to treat a migraine attack.

“Our study does not support the hypothesis that botulinum toxin A is effective in the prophylactic treatment of migraine,” the researchers conclude.

“However,” they add, “it might be that other injection sites and other doses of botulinum toxin A are effective in a defined subgroup of patients.”

SOURCE: Cephalalgia, October 2004.