OnabotulinumtoxinA Wear-off Phenomenon in the Treatment of Chronic Migraine

Objective: To evaluate the frequency and features of onabotulinumtoxinA (onabotA) wear-off in chronic migraine (CM). Background: Clinical experience suggests that patients with CM frequently perceive onabotA treatment duration <12 weeks, but this phenomenon has not been well explored. Methods: This study was a retrospective chart review of patients (n = 143) with CM initiated on onabotA over a 2-year period. Wear-off was considered present with the phrase documented, a quantitative headache day increase, or increased use of abortive medications, bridging therapies or emergency department visits in the 6 weeks preceding the subsequent administration. Results: Wear-off was present in 90/143 patients (62.9%). Age, sex, medication overuse, psychiatric comorbidity, injector training level, and mean days between injections did not differ between the wear-off and no wear-off groups. Mean units injected per session in the wear-off group until first documented wear-off were significantly less vs no wear-off group (166.0 ± 13.1 vs 173.4 ± 10.3, P =.0005). Wear-off most commonly occurred 2-4 weeks before the next injection (43.3%) and after the very first injection (40.0%). Intramuscular ketorolac injections (33.3%) and peripheral nerve blocks (25.6%) were the most common bridge therapies used in the wear-off period. Conclusions: Most patients with CM receiving onabotA experience wear-off. Clinicians may consider increasing the units used from the treatment onset to reduce the frequent need for bridging therapies.