title: Botulinum toxin type A as an effective prophylactic treatment in primary headache disorders.
abstract: OBJECTIVE
  To measure the effect of botulinum toxin type A (Botox, Allergan, Inc, Irvine, CA) treatment in 271 patients diagnosed with headache in accordance with International Headache Society (IHS) criteria.
  
  
  BACKGROUND
  Botulinum toxin type A has shown promise for the treatment of headache in several clinical trials, but uncertainty remains as to how botulinum toxin type A optimally should be used for treating headache and which patients are best suited for this treatment.
  
  
  METHODS
  This was a retrospective chart review of all patients who received botulinum toxin type A for the treatment of headache from January 1999 to February 2002. Patients were injected with an average dose of 63.2 U (SD, 14.5) of botulinum toxin type A on 2 or more visits, with treatments involving a "fixed-site" or a "follow-the-pain" (or a combination of both) approach. In the fixed-site approach, botulinum toxin type A was injected into the procerus, corrugator, frontalis, and temporalis muscles. In the follow-the-pain approach, botulinum toxin type A was injected into a combination of the procerus, corrugator, frontalis, temporalis, occipitalis, trapezius, and/or semispinalis capitis muscles. The primary outcomes for the trial were the reduction in headache days per month or headache intensity (0 to 3 scale) (or both) from baseline. Patients were diagnosed according to IHS criteria and subsequently classified into the following categories: chronic daily headache (more than 15 headache days per month), episodic tension-type headache, episodic migraine, and "mixed" HA (less than 15 headache days per month, combination of migraine and tension-type headache).
  
  
  RESULTS
  Treatment period was an average of 8.6 months (SD, 6.4); patients received an average of 3.4 doses (SD, 1.6) 3 months apart. Of the 271 patients, 29 (10.7%) had episodic migraine, 17 (6.3%) had episodic tension-type headache, 71 (26.2%) had mixed headache, and 154 (56.8%) had chronic daily headache. Two-hundred fifty-six patients had data for the number of headache days per month, 117 had data for headache intensity, and all 271 had data for headache days or headache intensity. Botulinum toxin type A treatment significantly reduced the number of headache days per month from 18.9 (SD, 10.3) to 8.3 (SD, 8.9) (n=256, P<.001)--a 56% reduction. Headache intensity decreased from 2.4 points (SD, 0.6) to 1.8 points (SD, 0.8) (n=117, P<.001)--a 25% reduction. Of 263 patients surveyed, 225 (85.6%) reported improvement in headache frequency and intensity. There was no correlation of effect/lack of effect with reason for treatment, duration/number of treatments, injection technique, mean/total dose, age, gender, or comorbidity. Approximately 95% of patients did not experience medication side effects.
  
  
  CONCLUSIONS
  These results suggest that botulinum toxin type A may be an effective and safe prophylactic treatment for a variety of moderate to severe chronic headache types.
authors.affiliation: San Diego, CA 92130, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Blumenfeld
mesh_terms: D001763:Blepharoptosis / Q000139:chemically induced; D019274:Botulinum Toxins, Type A / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D020773:Headache Disorders / Q000517:prevention & control*; D006801:Humans; D007273:Injections, Intramuscular / Q000379:methods; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000139:chemically induced; D009465:Neuromuscular Agents / Q000009:adverse effects / Q000627:therapeutic use*; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A