Real world Australian evidence supports the efficacy of Botulinum toxin (Botox) injections for the treatment of chronic migraine in adults.
A retrospective study of more than 200 patients from seven neurology practices across Victoria, Queensland, NSW, WA and the ACT found a high response rate (a ≥50% reduction in symptoms) of 74%.
Patients in the study met PBS eligibility criteria for onabotulinumtoxinA and were treated according to the Prescribing Information with up to 40 intramuscular injections into the head and neck.
The study, led by Melbourne neurologists Dr Catherine Stark and Professor Richard Stark, found the number of headache days per month dropped from 25.2 at baseline to 10.6 after two treatment cycles.
Severe headache days dropped from 12 to 3.8 per month while migraine days dropped from 15.3 to 5.8 per month.
There was also a corresponding and significant change in the mean score on the 6-item Headache Impact Test (HIT-6) from 68.2 to 56.4 after two treatment cycles.
There were fewer missed days at school or work after treatment (8.5 v 3.0 days per month) and less frequent use of acute pain medications including opioids (19.2 v 7.4 days/month).
Review of the medical records revealed no serious adverse events attributable to onabotulinumtoxinA.
“These results demonstrate the clinical benefit of onabotulinumtoxinA treatment to the lives of Australian patients with CM under real-world conditions,” the study said.
It noted that codeine-containing analgesics were available without prescription during the study period and that overuse was a relatively common problem.
“The reductions in acute pain medication use seen in this analysis were statistically significant and may be clinically important, given the existing societal issues surrounding opioid dependence.”
They also noted their response rate of 74% was higher than the 50% seen in earlier randomised controlled trials.
“A contributing factor to the improved response rate at 2 treatment cycles in private practice in Australia in comparison to the PREEMPT trials might include the Australian practitioners having an increased familiarity with injection techniques since the PREEMPT trials were conducted.”
The findings are published in the Journal of Headache and Pain.