RESUMO
BACKGROUND: OnabotulinumtoxinA (OnabotA) is effective in Chronic Migraine (CM) during first year of treatment and longer. In real clinical setting, CM patients with acute Medication Overuse (MO) or concurrently receiving oral preventatives are treated with OnabotA. We aim to assess evolution of CM patients beyond first year on OnabotA. METHODS: Data were retrospectively collected in three headache units. We analyzed cases who had received at least five sessions of OnabotA according to PREEMPT protocol. We continued OnabotA therapy when a reduction of number of headache days of at least 30% was achieved. RESULTS: We included 115 patients (98 females, 17 males) who completed 7.6 ± 2.3 (5-13) OnabotA procedures. Previously they had not responded to topiramate and, at least, one other preventative. Age at inclusion was 45.3 ± 12 (14-74) years, and latency between CM onset and OnabotA therapy was 43.1 ± 38.2 (6-166) months. At first OnabotA session 92 patients (80%) fulfilled MO criteria and 107 (93%) received a concurrent oral preventative. In 42 cases (36.5%) OnabotA dose was increased over 155 units. After first year in 57 out of 92 patients (61.9%) MO was discontinued. Among those receiving preventatives, in 52 out of 107 they were retired (48.6%). In 22 cases (19.1%) OnabotA administration was delayed to the fourth or fifth month and in 12 (10.4%) it was temporally stopped. Finally, in 18 patients (15.7%) OnabotA was discontinued due to lack of efficacy beyond first year of treatment. CONCLUSION: Our results suggest that discontinuation of acute medication overuse and oral preventive therapies are achievable objectives in long-term using of OnabotA in CM patients.