Eletriptan, sold under the brand name Relpax and used in the form of eletriptan hydrobromide, is a second-generation triptanmedication intended for treatment of migraineheadaches. It is used as an abortive medication, blocking a migraine attack which is already in progress. Eletriptan is marketed and manufactured by Pfizer.
Eletriptan was approved by the United States Food and Drug Administration (FDA) in December 2002, for the acute treatment of migraine with or without aura in adults. It is available only by prescription in the United States, Canada, and Australia. It is not intended for the prophylactic therapy of migraine or for use in the management of hemiplegic or basilar migraine. It is available in 20mg and 40mg strengths.
Contraindications
Eletriptan is contraindicated in patients with various diseases of the heart and circulatory system, such as angina pectoris, severe hypertension, and heart failure, as well as in patients that have had a stroke or heart attack. This is due to the unusual side effect of coronary vasoconstriction due to serotonin 5-HT1B receptor agonism, which can precipitate a heart attack in those already at risk. It is also contraindicated in severe kidney (renal) or liver (hepatic) impairment due to its extensive liver metabolism through CYP3A4.
Side effects
Common side effects include hypertension, tachycardia, headache, dizziness, drowsiness, and symptoms similar to angina pectoris. Severe allergic reactions have been seen rarely.
Interactions
Strong inhibitors of the liver enzyme CYP3A4, such as erythromycin and ketoconazole, significantly increase blood plasma concentration of eletriptan and should be separated by at least 72 hours. Ergot alkaloids, such as dihydroergotamine, add to the drug's hypertensive effect and should be separated by at least 24 hours.
Notes: The smaller the value, the more avidly the drug binds to the site. All proteins are human unless otherwise specified. Refs:
Eletriptan is believed to reduce swelling of the blood vessels surrounding the brain. This swelling is associated with the head pain of a migraine attack. Eletriptan blocks the release of substances from nerve endings that cause more pain and other symptoms like nausea, and sensitivity to light and sound. It is thought that these actions contribute to relief of symptoms by eletriptan.
Eletriptan has no significant affinity or pharmacological activity at adrenergicα1, α2, or β; dopaminergicD1 or D2; muscarinic; or opioid receptors. Eletriptan could be efficiently co-administered with nitric oxide synthase (NOS's) inhibitors for the treatment of NOS-dependent diseases (US patent US 2007/0254940).
Two theories have been proposed to explain the efficacy of 5-HT1 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.
The drug is also notable in being a weak serotonin 5-HT2A receptor agonist (EC50Tooltip half-maximal effective concentration = 851nM), albeit with about two to three orders of magnitude lower activational potency than at the serotonin 5-HT1B and 5-HT1D receptors.
Eletriptan is sold in the United States, Canada, Australia, and the United Kingdom under the brand name Relpax, and in several other countries under the brand name Relert.[citation needed]
In the United States, Relpax is marketed by Viatris after Upjohn was spun off from Pfizer.
↑van den Brink M (22 December 1999). "Coronary Side Effects of Antimigraine Drugs From Patient to Receptor". RePub, Erasmus University Repository. Retrieved 19 June 2025. Table 1.2 Receptor binding properties (pKi values) of sumatriptan and second-generation triptans at 5-HT receptors. [...]
↑Deleu D, Hanssens Y (July 2000). "Current and emerging second-generation triptans in acute migraine therapy: a comparative review". J Clin Pharmacol. 40 (7): 687–700. doi:10.1177/00912700022009431. PMID10883409.
↑Cole P, Rabasseda X (March 2001). "Migraine headache treatment with eletriptan, a second-generation serotonin receptor agonist". Drugs Today (Barc). 37 (3): 159–171. doi:10.1358/dot.2001.37.3.614851. PMID12783088.
12Rubio-Beltrán E, Labastida-Ramírez A, Haanes KA, van den Bogaerdt A, Bogers AJ, Zanelli E, etal. (December 2019). "Characterization of binding, functional activity, and contractile responses of the selective 5-HT1F receptor agonist lasmiditan". British Journal of Pharmacology. 176 (24): 4681–4695. doi:10.1111/bph.14832. PMC6965684. PMID31418454. TABLE 1 Summary of pIC50 (negative logarithm of the molar concentration of these compounds at which 50% of the radioligand is displaced) and pKi (negative logarithm of the molar concentration of the Ki ) values of individual antimigraine drugs at 5‐HT receptors [...] TABLE 2 Summary of pEC50 values of cAMP (5‐HT1A/B/E/F and 5‐HT7), GTPγS (5‐HT1A/B/D/E/F), and IP (5‐HT2) assays of individual antimigraine drugs at 5‐HT receptors [...]
↑Perez, M., Halazy, S., Pauwels, P.J., Colpaert, F.C., John, G.W. (1999). "F-11356". Drugs of the Future. 24 (6): 0605. doi:10.1358/dof.1999.024.06.537284. Retrieved 23 June 2025.
