5-carboxamidotryptamine (5-CT) is a 5-HT1 agonist with high affinity at 5-HT1A, 5-HT1B, 5-HT1D, 5-HT5 and 5-HT7 receptors. As one of the first compounds reported active at 5-HT1B, 5-carboxamidotryptamine was originally investigated as a potential treatment for migraine. During preclinical studies, 5-CT was found to cause vasodilatation of carotid circulation and hypotension in animals, effects that were later attributed to potent agonist activity at 5-HT7. Subsequent structural modifications of 5-CT led to the discovery of the anti-migraine drug sumatriptan. 5-CT is primarily used as a pharmacological tool for study of 5-HT1 and 5-HT7 mediated functional responses.