THE ROLE OF BOTULINUM TOXIN IN CHRONIC MIGRAINE: A NARRATIVE REVIEW

Background Migraine is a chronic and highly disabling neurological disorder and one of the leading causes of years lived with disability worldwide. Chronic migraine is associated with substantial impairment of quality of life, social functioning and mental health, and remains a major therapeutic challenge due to limited efficacy and tolerability of many preventive treatments. Aims The aim of this narrative review was to synthesize current evidence on the role of botulinum toxin type A in the management of migraine, with a primary focus on chronic migraine, in order to support rational, evidence based and individualized preventive treatment strategies. Methods A narrative literature review was conducted using the PubMed database. English language full text publications published between March 2010 and December 2025 were screened. Meta analyses, randomized controlled trials, cohort studies, original research articles and review papers addressing the use of botulinum toxin in adult migraine populations were considered. A total of 46 publications meeting predefined inclusion and exclusion criteria were included in the qualitative synthesis. Results Randomized controlled trials PREEMPT 1 and PREEMPT 2, together with subsequent meta analyses and real world studies, consistently demonstrate the efficacy of onabotulinumtoxinA in chronic migraine. Treatment is associated with a reduction in the number of migraine days, decreased frequency, intensity and duration of attacks, improvement in health related quality of life and a reduction in medication overuse. No clinically relevant benefit has been demonstrated in episodic migraine. Compared with oral preventive therapies, onabotulinumtoxinA shows better tolerability and lower rates of treatment discontinuation due to systemic adverse effects. Conclusions The available evidence supports onabotulinumtoxinA as an effective and well tolerated preventive treatment option for chronic migraine. Its local mechanism of action and favorable safety profile make it particularly relevant for patients who do not respond to or cannot tolerate oral preventive medications. Further research is required to clarify long term outcomes and to refine clinical predictors of treatment response.