Botulinum Toxin for Migraine Prophylaxis

January 25, 2016
Heidi Moawad, MD

Does prophylactic onabotulinumtoxinA benefit patients with migraine or are they experiencing a placebo effect?

Headaches are the most common neurological ailment, and migraine headaches can interfere with optimal functioning at work, at home, and in relationships. The persistent pain and the often-overwhelming symptoms of dizziness, disorientation, neck pain, and nausea can contribute to depression and anxiety for many migraine sufferers. While few migraine sufferers can develop a sense of predictably to migraine attacks, most live with the apprehension that a debilitating migraine can strike at any time.

For neurologists, this makes prophylactic treatment an important aspect of the approach to migraine treatment. There are several effective prophylactic medications with relatively few side effects. However, given the prevalence of migraine, a number of migraine sufferers experience intolerable side effects from oral prophylactic treatments.

Prophylactic onabotulinumtoxinA had been used to prevent migraine headaches. Given the popularity of botulinum toxin for the treatment of wrinkles, one of the frequent considerations is whether patients really benefit in terms of migraine prophylaxis or whether many patients are using botulinum toxin for cosmetic reasons. Additionally, the obvious placebo effect of receiving an injection can alter the patient’s perception of treatment success and the provider’s perception of efficacy. 

Surprisingly, in studies of tension headache prophylaxis, botulinum toxin was not found to be effective. Given what is known and accepted about the mechanism of action, it would be logical that it might be helpful in the prevention of tension headaches. Also surprisingly, botulinum toxin injections have been useful in migraine prophylaxis in several small trials. The mechanism of action of botulinum toxin for the treatment of muscle spasticity has been well understood for many decades. Yet, how botulinum toxin can impact migraine on a biochemical basis is not well understood. 

One of the relatively larger trials evaluated 1005 patients who received 5 cycles of onabotulinumtoxinA at intervals of 12 weeks over a 56-week period and 492 patients who received 2 initial cycles of placebo injection and 3 cycles of onabotulinumtoxinA injections. The patients who did not receive any placebo experienced a significantly greater reduction of headaches when compared to the group that received 2 cycles of placebo treatment. Additionally, the Severe Headache Impact Test score and the Migraine Specific Quality of Life scores were significantly different between the 2 groups, with the full treatment group scoring much better. 

Side effect profile between the 2 groups was also quite different, with the all-treatment group experiencing 34.8% side effects through the 56-week period compared to only 12.4% side effects in a group who received only placebo for the first 2 cycles. Side effects included muscle weakness, injection site pain, and eyelid ptosis. 

Overall, botulinum toxin may be a useful approach for some patients who cannot tolerate systemic effects of oral prophylactic migraine medication. One disadvantage is the need for repeated injections every 12 weeks. Given that it is a recently developed migraine prophylaxis treatment, it is not yet clear whether long-term desensitization to migraine pain and symptoms could result in declining need for migraine treatment over time.

Do you prefer to use oral medications or injections for migraine prophylaxis for your chronic migraine patients?

References:

Gooriah R, Ahmed F. OnabotulinumtoxinA for chronic migraine: a critical appraisal. Ther Clin Risk Manag. 29 June 2015.

Aurora SK, et al. OnabotulinumtoxinA for chronic migraine: efficacy, safety, and tolerability in patients who received all five treatment cycles in the PREEMPT clinical program. Acta Neurol Scand. 2014 Jan; 129(1): 61-70.

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