Rimegepant

The currently accepted theory of migraine pathophysiology considers dysfunction of the central nervous system, in particular the trigeminal ganglion, to be the root cause behind the condition. Activation of the trigeminal ganglion triggers the stimulation of trigeminal afferents that project to the spinal cord and synapse on various pain-sensing intra- and extracranial structures, such as the dura mater. Pain signals are then further transmitted via second-order ascending neurons to the brainstem, hypothalamus, and thalamic nuclei, and from there to several cortical regions (e.g. auditory, visual, motor cortices). The trigeminal ganglion appears to amplify and perpetuate the migraine headache pain through the activation of perivascular fibers and the release of molecules involved in pain generation, such as calcitonin gene-related peptide (CGRP).

The α-isoform of CGRP, expressed in primary sensory neurons, is a potent vasodilator and has been implicated in migraine pathogenesis - CGRP levels are acutely elevated during migraine attacks, return to normal following treatment with triptan medications, and intravenous infusions of CGRP have been shown to trigger migraine-like headaches in migraine patients. In addition to its vasodilatory properties, CGRP appears to be a pronociceptive factor that modulates neuronal excitability to facilitate pain responses.

Rimegepant is an antagonist of the calcitonin gene-related peptide receptor - it competes with CGRP for occupancy at these receptors, preventing the actions of CGRP and its ability to amplify and perpetuate migraine headache pain, ultimately terminating the headache.