Botox and placebo similar for preventing migraines

NEW YORK (Reuters Health) - Multiple treatments with Botox injections into muscles of the head and neck are not significantly better than inactive "placebo" injections for preventing migraine episodes, according to European and US researchers.

In the medical journal Cephalalgia, Dr. Maja Relja of the Medical University of Zagreb, Croatia and colleagues point out that botulinum toxin A, or Botox, has shown promise in previous studies against chronic daily headaches, but the results of episodic migraine studies have been mixed.

To investigate further, the researchers studied 495 patients with migraine who were randomly assigned to injections of various doses of Botox or saline placebo over three 90-day treatment periods. Several injections were made into each of seven muscle groups of the head and neck during each treatment session.

Before treatment, the participants experienced about 4.5 migraine episodes every 30 days. After treatment, the frequency of migraine headaches in any 30-day period was reduced by about 1.6 episodes in the active treatment groups and by about 1.4 in the placebo group. This difference was not significant from a statistical standpoint.

The researchers highlight the strong placebo effect seen in their study. This might be explained, they suggest, by the fact that patients "may perceive an injectable placebo as having greater analgesic potency than an oral placebo."

SOURCE: Cephalalgia, July 2007.