REVIEW Eletriptan binds with high affinity to 5-HT1B, 5-HT1D and 5-HT1F receptors, has modest affinity for 5-HT1A, 5-HT1E, 5-HT2B and 5-HT7 receptors, and little or no affinity for 5-HT2A, 5-HT2C, 5-HT3, 5-HT4, 5-HT5A and 5-HT6 receptors. Eletriptan has no significant affinity or pharmacological activity at adrenergic alpha1, alpha2, or beta; dopaminergic D1 or D2; muscarinic; or opioid receptors. Two theories have been proposed to explain the efficacy of 5-HT receptor agonists in migraine. One theory suggests that activation of 5-HT1 receptors located on intracranial blood vessels, including those on the arteriovenous anastomoses, leads to vasoconstriction, which is correlated with the relief of migraine headache. The other hypothesis suggests that activation of 5-HT1 receptors on sensory nerve endings in the trigeminal system results in the inhibition of pro-inflammatory neuropeptide release.