Research on Botulinum Toxin (Botox) for Migraine is Not Convincing
February 15, 2011 — Despite botulinum toxin A (Botox) being approved for use in chronic migraines, published evidence on the effectiveness of this treatment for headaches is unconvincing, according to an article appearing in Drug and Therapeutic Bulletin (DTB).
The evidence from two published double-blind studies does not suggest a huge benefit, said Dr. Iheanacho, author of article. "We're not talking about abolition of chronic migraine headaches here; we're talking about a slight reduction."
In addition, Botulinum toxin A treatment for migraine is costly, and the toxin can actually cause headaches, pain, stiffness, and muscle spasms, "which is obviously not an ideal outcome," said Dr. Iheanacho.
"When you consider all those factors together, it doesn't add up to much benefit in our view," he said.
Published Trials
The DTB article describes 2 published double-blind, randomized, placebo-controlled trials of botulinum toxin A in chronic migraine. The first included 679 adults who received either the toxin or placebo every 12 weeks in 31 injections in the head and neck. This study found that the frequency of headache episodes at week 24 did not significantly differ between the two groups - the placebo did equally as well as the botulinum toxin injections.
The second study was identical in design, except that it measured headache days rather than headache episodes, but had the same basic results.
Questionable Benefit
To further discount any benefit of botulinum toxin A injections, it is known that these injections produce effects noticeable to those receiving the toxin but not the placebo. "If people knew or could tell or could guess that they got Botox because of the effect on their head and neck muscles, you have to worry about whether any benefits you see are an added placebo effect rather than one specifically attributable to the drug," said Dr. Iheanacho.
Cost Factor
Another drawback to botulinum toxin A use in headaches is the cost. Every treatment (31-39 injections) costs about $443 and is repeated every 12 weeks, so the annual cost is $1600.
All these factors together suggest that botulinum toxin A does not add significantly to the treatment of migraine, said Dr. Iheanacho. "We don't think it offers much to people with chronic migraine as far as we can tell from the evidence available."
DTB is owned and published by BMJ Group, a wholly owned subsidiary of the British Medical Association.
