Telcagepant (MK0974) is one of several calcitonin-gene-related peptide antagonists in development as a potential treatment for acute migraine attacks and is the first orally available drug in this class. Preclinical and clinical data are reviewed, which support the efficacy and tolerability of telcagepant for the treatment of migraine, particularly for patients unable to tolerate, or who have cardiovascular contraindications to, triptans.