Migraine is a
chronic headache disorder manifesting in attacks lasting 4-72 hours. Characteristics of
headache are unilateral location, pulsating quality, moderate or severe intensity, aggravation by routine physical activity, and association with
nausea,
photophobia and
phonophobia. The
migraine aura is a complex of neurological symptoms, which occurs just before or at the onset of
migraine headache.
Botulinum toxin A represents a completely new option for patients with
chronic pain conditions. Numerous retrospective open-label chart reviews and 4 double-blind, placebo-controlled studies have demonstrated that
botulinum toxin type A is significantly effective in
migraine prophylaxis and reduces the frequency, severity, and disability associated with
migraine headaches. Studies have generally reported a good and consistent efficacy. The differential
therapeutic use of
botulinum toxin appears to be worth attempting in
migraine patients with the following characteristic features: (1) Muscular stress as
migraine trigger, e. g., in craniocervical
dystonia, pericranial painful muscular trigger points or tender points, oromandibular dysfunction, (2) concurrent chronic
tension-type headache with the aggravating factors of muscular stress or oromandibular dysfunction, (3) chronic
migraine with frequent
migraine attacks on more than 15 days per month for longer than 3 months and if other therapeutic options have been either ineffective or have not been tolerated. The use of the agent does not cause CNS side effects.
Migraine patients in particular, often suffer greatly, as a result of the adverse effects of the drugs used, from
fatigue,
dizziness, reduced concentration, loss of appetite,
weight gain,
hair loss and changes in libido. These side effects are not known in association with
botulinum toxin A. To date, neither organic damage nor allergic complications have been reported. Thus, both the tolerability and the safety of this therapeutic measure are high. The mode of action by which
botulinum toxin is effective in
migraine prophylaxis is not fully understood and is under investigation. Currently, a number of other randomized, placebo-controlled, clinical trials are being conducted to evaluate the efficacy, optimal dosing, and side-effect profile of
botulinum toxin type A in the prophylaxis of
migraine and other
headache entities.