Role of Calcitonin Gene-Related Peptide on the Gastrointestinal Symptoms of Migraine-Clinical Considerations: A Narrative Review.

Calcitonin gene-related peptide (CGRP) is involved in several of the pathophysiologic processes underpinning migraine attacks. Therapies that target CGRP or its receptor have shown efficacy as preventive or acute treatments for migraine. Two small-molecule CGRP receptor antagonists (rimegepant and ubrogepant) are approved for the acute treatment of migraine, and 4 monoclonal antibodies (eptinezumab, erenumab, fremanezumab, and galcanezumab) are approved for migraine prevention; erenumab targets the canonical CGRP receptor, the others CGRP ligand. CGRP plays a role in gastrointestinal nociception, inflammation, gastric acid secretion, and motility. Nausea and vomiting are among the gastrointestinal symptoms associated with migraine, but individuals with migraine may also experience functional upper and lower gastrointestinal comorbidities, such as gastroesophageal reflux disease, gastroparesis, functional diarrhea or constipation, and irritable bowel syndrome. Although gastrointestinal symptoms in migraine can be treatment-related, they may also be attributable to increased CGRP. In this review, we summarize the epidemiologic evidence for associations between migraine and gastrointestinal disorders, consider the possible physiologic role of CGRP in these associations, and review the clinical occurrence of gastrointestinal events in patients with migraine receiving CGRP-based therapies and other migraine treatments. Because patients with migraine are at an increased risk of comorbid and treatment-related gastrointestinal effects, we also propose a patient-management strategy to mitigate these effects.