Calcitonin Gene-Related Peptide Antagonists as a Savior in Episodic and Chronic Migraine: A Review

Headaches due to migraine are the second leading cause of disability in the world. Migraine can be classified as episodic migraine (EM) and chronic migraine (CM). The course of the disease starts from an aura followed by 4-72 hours of bouts of throbbing, mostly unilateral headache associated with nausea, photo/phonophobia with/without neurological deficit. The pathophysiology of migraine remains debatable and many drugs are used to help control migraine attacks with little or no benefit. However, patient compliance remains a reason for over and underdosing of these medications. The calcitonin gene-related peptide (CGRP), a vasoactive peptide is known to contribute to the disease course. Much work is done on antagonizing the receptor or the molecule itself. For this purpose, genetically engineered monoclonal antibodies are being utilized for long-term reduction in morbidity and prevention of migraine headaches. The four to name are: galcanezumab, fremanezumab, eptinezumab, and erenumab. The purpose of this review is to shed light on the use of these monoclonal antibodies, completed and recruiting trials, and the role of these medications in the prevention of not only EM and CM but also in medication overuse headaches.