A multicentre case series of patients with chronic migraine (CM) treated with monoclonal antibodies directed against calcitonin gene-related peptide (CGRP-mAbs) switching were developed. The effectiveness and safety of CGRP-mAbs switching as a preventive treatment for CM in clinical practice were recorded. Effectiveness was measured by ≥50% reduction of monthly migraine days in respect to baseline and reduction in pain intensity. Safety was analysed through adverse events (AEs) and treatment discontinuations. Seven patients were included. The reason for switching was non-response in all cases. Two patients presented a response to the first CGRP-mAb, but the effect was lost after 3 months. The remaining five patients were non-responders. Response to the second CGRP-mAb was observed in three patients, one of them for >3 months. Less than half of the patients previously treated with a CGRP-mAb responded to switching with a second CGRP-mAb. AEs were rare, with no treatment discontinuations.