Raynaud's Phenomenon Associated With Calcitonin Gene-Related Peptide Monoclonal Antibody Antagonists

Two cases are reported of migraineurs who reported Raynaud's phenomenon (RP) exacerbated while taking monoclonal antibodies to the calcitonin gene-related peptide (CGRP) ligand (fremanezumab and galcanezumab) and 1 case of new onset RP while taking the CGRP receptor antagonist (erenumab). The prevalence of primary and secondary RP, causes of secondary RP, co-morbidity with migraine, and medications which might induce or exacerbate RP are reviewed. The pathophysiology of how CGRP monoclonal antagonists might exacerbate or induce RP is discussed. The cases suggest but do not prove causation.