Sumatriptan is a selective serotonin (5-HT1B/1D) receptor agonist, commonly known as a 'triptan'. It is a first-line abortive therapy for the acute treatment of moderate to severe migraine attacks with or without aura, and for cluster headaches. It works by causing vasoconstriction of cranial blood vessels, inhibiting neurogenic inflammation, and blocking pain pathways in the trigeminal system.
Adult: For Migraine: A single 50mg tablet, taken with fluids at the onset of migraine pain. If headache recurs, a second dose may be taken after at least 2 hours. Maximum: 100mg in a 24-hour period. For Cluster Headache: Oral route is less effective; 50mg dose can be used, but max 100mg/24h.
Note: Swallow tablet whole with a glass of water. Can be taken with or without food. Do not crush or chew. Take at the earliest sign of migraine headache. If no response to the first dose, do not take a second dose for the same attack. Do not use for more than 10 headache days per month to avoid MOH.
Sumatriptan binds with high affinity to vascular 5-HT1B receptors and neuronal 5-HT1D receptors. Activation of 5-HT1B receptors on dilated intracranial extracerebral blood vessels causes vasoconstriction, reversing the vasodilation associated with migraine. Activation of presynaptic 5-HT1D receptors inhibits the release of pro-inflammatory neuropeptides (like CGRP and substance P) from trigeminal sensory nerves, reducing neurogenic inflammation and pain signal transmission in the trigeminal-vascular system.
Pregnancy: Category C: Animal studies have shown adverse effects. There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus. Should be avoided in the third trimester due to theoretical risk of uterine vasoconstriction.
Driving: May cause dizziness, drowsiness, or visual disturbances. Patients should not drive or operate machinery until they are sure they are not affected.
| Monoamine Oxidase-A Inhibitors (e.g., Moclobemide, Clorgiline) | Markedly increased sumatriptan plasma levels (up to 7-fold). Increased risk of serotonin syndrome. | Contraindicated |
| Selective Serotonin Reuptake Inhibitors (SSRIs e.g., Sertraline, Escitalopram) / SNRIs (e.g., Venlafaxine) | Increased risk of serotonin syndrome (weakness, hyperreflexia, incoordination). | Major |
| Ergot Alkaloids (e.g., Ergotamine, Dihydroergotamine) | Prolonged vasospastic reactions. A 24-hour gap is mandatory between doses. | Contraindicated |
| Other Triptans (e.g., Rizatriptan, Zolmitriptan) | Additive vasoconstrictive effects. Risk of serotonin syndrome. | Contraindicated |
| 5-HT1 agonists (e.g., Buspirone) | Potential for additive serotonergic effects. | Moderate |
| St. John's Wort | Potential increased serotonergic effects. | Moderate |
| Propranolol | Increases sumatriptan plasma concentration by about 50%. | Moderate |