CGRP inhibitors for migraine prophylaxis: a safety review

Introduction: Since calcitonin gene-related peptide (CGRP) plays an important role in the pathophysiology of migraine via the activation of the trigeminovascular system, the newest prophylactic treatments directly block CGRP or its receptor. However, the safety of these novel antimigraine drugs is not yet sufficiently established. Areas covered: Based on the blockade of CGRP or its receptor, this review considers: (i) the effects of the novel prophylactic antimigraine drugs (i.e. gepants and monoclonal antibodies) in clinical trials; and (ii) the potentially negative effects of blocking CGRP or its receptor in terms of safety. Expert opinion: In the last decade, clinical trials have demonstrated the efficacy of new drugs for the preventive treatment of migraine which aim to (i) block CGRP or its receptor; (ii) increase tolerability as compared to the currently available prophylactics; and/or (iii) be more effective and safer than other treatments. However, these trials are limited to study the safety on the short term, and a cardiovascular risk with prolonged use cannot be excluded. Clearly, basic science experimental studies and long-term clinical trials (i.e. Phase IV) are required to delineate the safety of the newest prophylactic antimigraine drugs without causing unwanted side effects due to chronic CGRP (receptor) blockade.