MK-3207 is a highly potent and orally bioavailable small molecule antagonist of the calcitonin gene-related peptide (CGRP) receptor, demonstrating an in vitro IC50 of 0.12 nM and a Ki of 0.024 nM for the human receptor with exceptional selectivity over the related human AM1, AM2, CTR, and AMY3 receptors, though it exhibits lower affinity for CGRP receptors from other species such as canine and rodent; in vitro studies confirm its potent antagonism of human and rhesus monkey CGRP receptors (K(i) = 0.024 nM), and in vivo models show it produces a concentration-dependent inhibition of dermal vasodilation, requiring plasma concentrations of 0.8 nM and 7 nM to block 50% and 90% of the blood flow increase, respectively.