Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies

Department Chair

John Cavenagh, PhD, PA-C


OBJECTIVE: The objective of this selective EBM review is to determine whether or not onabotulinumtoxinA (Botox®) is effective in reducing the number of chronic migraines (CM) in patients 18-65 years old? Study Design: Review of three published, double blind randomized controlled trials were used for this review, which were found on PubMed; were selected based on their relevance to the clinical question and if they included patient oriented outcomes.

OUTCOMES MEASURED: The outcomes measured were headache/migraine free days measured by >50% responder rate analysis, the Treatment Responder Rate based on Physician Global Assessment, and total adverse events reported by the participants.

RESULTS: In the study by Mathew et al, onabotulinumtoxinA reported >50% reduction in HA/migraine days at 3,6,9 months and was consistent if not better when compared to topiramate (TOPAMAX®). A study by Cady et al. showed the treatment responder rate based on Physician Global Assessment 9-point scale (+4= clearance of signs and symptoms and -4 =very marked worsening), that by 12 weeks onabotulinumtoxinA treatment when compared to topiramate had improved chronic migraines (CM) by 79.2% verses 70.8%. Dodick et al, illustrated that onabotulinumtoxinA against placebo showed a >50% responder rate starting at week 4 and including 24 weeks. Dodick et al, also looked at total adverse events (AE). Most adverse events (AE) were mild or moderate in severity and included neck pain, mild fatigue, nausea and muscular weakness, and resolved without sequelae.

CONCLUSIONS: The results of these three randomized controlled trials demonstrate that onabotulinumtoxinA is safe and effective at treating chronic migraines when compared to placebo and topiramate.