A 2 years prospective evaluation study on onabotulinumtoxinA 195 U in chronic migraine

Background: OnabotulinumtoxinA (Botox®) is the first and so far the only treatment to receive a specific license for prevention of chronic migraine (CM). In our Headache Clinic the therapy with onabotulinumtoxinA is routinely administered to CM patients on a daily basis since 2001. Preventive treatment with onabotulinumtoxinA was offered to all patients that were 1) adults; 2) fulfilling the ICHD-II criteria for CM with or without analgesic overuse; and 3) with contraindications or lack of efficacy or tolerability to other preventive drugs. Exclusion criteria were coexistent of neuromuscular disorders, psychiatric diseases considered incompatible with such kind of treatment, pregnancy and breastfeeding.