Background: Chronic migraine is a neurological disorder described as refractory to preventive treatments. Based on the PREEMPT study, the National Institute for Health and Clinical Excellence (NICE) and the FDA approved, in 2010, the use of Botulinum Toxin type A (BoNT/A) to treat refractory chronic migraine. Objectives: To review the effectiveness of the use of BoNT/A in the treatment of refractory migraine. Methods: Bibliographic review based on PubMed database, using the descriptors “migraine” and “botulinum toxin”. Clinical trials, meta-analyzes and randomized controlled tests, from the last five years, were defined as inclusion criteria. Results: Sanz et al., (2016) infiltrated BoNT/A in 69 patients - mean age 43 years old, 88.4% women, mean infiltration rate was 2,0. The reduction of headache days and pain intensity was 48.5% and 20.5%, respectively, both statistically significant (p <0.006). Ion et al., (2018) intervened 61 patients - mean age 50 years old, 87% women, mean infiltration of 3.5. 73% showed a reduction greater than 50% for the frequency of migraine episodes, 48% for headache days and 48% for drug use. Dodick et al., (2019) applied BoNT/A in 688 patients - 696 received placebo. The severity and frequency of pain showed a statistically significant reduction (p < 0.001) after the first week of treatment in relation to the control group. Conclusions: The use of BoNT/A to treat refractory chronic migraine proves to be effective, although there is need for studies with larger samples to ensure its effectiveness.
The processes underlying chronic migraine pathophysiology and its treatment with botulinum toxin type A