Rizatriptan is a selective serotonin (5-HT1B/1D) receptor agonist, commonly known as a 'triptan'. It is a second-generation agent specifically indicated for the acute treatment of migraine with or without aura in adults. It is not intended for migraine prophylaxis. It works by causing vasoconstriction of cranial blood vessels, inhibiting neurogenic inflammation, and blocking pain pathways in the trigeminal system.
Adult: 5mg or 10mg as a single dose. The 5mg dose may be considered for patients on propranolol. If headache recurs, a second dose may be taken after at least 2 hours. Maximum: 30mg in 24 hours.
Note: Tablet: Swallow whole with water. Can be taken with or without food, but food may delay onset. Orally Disintegrating Tablet (ODT): Place on tongue, allow to disintegrate, and swallow with saliva. No water needed. Do not break or split ODT. Take at the first sign of a migraine headache. Not for prophylactic use.
Rizatriptan binds with high affinity to serotonin 5-HT1B and 5-HT1D receptors. Activation of 5-HT1B receptors on intracranial blood vessels, including those on the arteriovenous anastomoses, leads to vasoconstriction, reversing the vasodilation associated with migraine. Activation of 5-HT1D receptors on sensory nerve endings of the trigeminal system inhibits the release of pro-inflammatory neuropeptides (e.g., CGRP, substance P), thereby reducing neurogenic inflammation and pain signal transmission.
Pregnancy: Category C: Animal studies show adverse effects. No adequate, well-controlled studies in pregnant women. Use only if potential benefit justifies potential risk to the fetus.
Driving: May cause dizziness, somnolence, fatigue. Patients should not drive or operate machinery until they know how the drug affects them.
| Propranolol | Increases rizatriptan AUC by ~70%. Use 5mg dose; max 5mg/24h. | Major |
| Monoamine Oxidase-A Inhibitors (Moclobemide, Clorgyline) | Markedly increases rizatriptan plasma levels (contraindicated). | Contraindicated |
| Selective Serotonin Reuptake Inhibitors (SSRIs e.g., Sertraline, Fluoxetine) | Increased risk of serotonin syndrome (weakness, hyperreflexia, incoordination). | Major |
| Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs e.g., Venlafaxine) | Increased risk of serotonin syndrome. | Major |
| Ergot Alkaloids (Ergotamine, Dihydroergotamine) | Prolonged vasospastic reactions. Avoid within 24 hours of each other. | Major |
| Other Triptans (Sumatriptan, etc.) | Additive vasoconstrictive effects. Avoid within 24 hours. | Major |
| Sibutramine | Increased risk of serotonin syndrome. | Major |