RIZATRIPTAN BENZOATE
Clinical safety rating: avoid
Contraindicated (not allowed)
Selective serotonin 5-HT1B/1D receptor agonist; binds with high affinity to 5-HT1B and 5-HT1D receptors, leading to vasoconstriction of intracranial blood vessels and inhibition of trigeminal nerve transmission, thereby reducing migraine-associated neurogenic inflammation.
| Metabolism | Primarily metabolized by monoamine oxidase A (MAO-A) via oxidative deamination; minor metabolism by aldehyde oxidase. The major metabolite is the inactive N-desmethyl rizatriptan. |
| Excretion | Primarily hepatic metabolism via monoamine oxidase-A, with ~14% excreted unchanged in urine; total recovery of radioactivity in urine is ~82% (30% unchanged drug, 52% metabolites) and ~9% in feces over 24 hours. |
| Half-life | 2-3 hours in adults; clinically, no significant accumulation with multiple dosing. |
| Protein binding | 14% |
| Volume of Distribution | 140 L (approximately 2 L/kg in adults), indicating extensive tissue distribution. |
| Bioavailability | Oral: ~45% (due to first-pass metabolism); intranasal: ~42% (compared to subcutaneous sumatriptan); orally disintegrating tablet: ~45%. |
| Onset of Action | Oral: 30 minutes; orally disintegrating tablet: 30 minutes; intranasal: 10-15 minutes. |
| Duration of Action | 2-3 hours; headache relief often persists for up to 24 hours in responders, but duration may be shorter in some patients. |
5-10 mg orally at onset of migraine; may repeat after 2 hours if headache recurs; maximum 30 mg in 24 hours.
| Dosage form | TABLET, ORALLY DISINTEGRATING |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment. Not recommended in severe renal impairment (CrCl <30 mL/min) due to limited data. |
| Liver impairment | Not recommended in patients with severe hepatic impairment (Child-Pugh class C) due to absence of studies. For mild to moderate impairment (Child-Pugh A or B), no specific dose adjustment; use caution. |
| Pediatric use | Children 6-17 years: 5-10 mg orally at onset; may repeat after 2 hours; maximum 30 mg per 24 hours. Weight <40 kg: start 5 mg. Weight ≥40 kg: may use 10 mg. |
| Geriatric use | Elderly patients may have increased risk of adverse effects. Start at 5 mg; use caution with comorbidities and concomitant medications. No specific dose adjustment required; monitor cardiovascular status. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
MAOIs and other 5-HT1 agonists can have additive effects Contraindicated in ischemic heart disease and uncontrolled hypertension.
| Breastfeeding | Rizatriptan is excreted in human milk at very low levels; the milk-to-plasma ratio is approximately 0.07. The estimated infant dose is about 3% of the maternal weight-adjusted dose. Caution is advised; consider the developmental and health benefits of breastfeeding along with the mother's clinical need for rizatriptan and potential adverse effects on the breastfed infant. |
| Teratogenic Risk | Rizatriptan is classified as Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. In animal studies, rizatriptan was not teratogenic in rats or rabbits but was associated with embryo-fetal toxicity at maternotoxic doses. Use only if potential benefit justifies potential risk to the fetus. First trimester: no specific data, but theoretical risk of vasoconstriction. Second and third trimesters: may cause uterine contractions or reduced uterine blood flow. |
■ FDA Black Box Warning
None
| Common Effects | Dizziness |
| Serious Effects |
History of ischemic heart disease (angina, myocardial infarction, silent ischemia), coronary artery vasospasm (Prinzmetal's angina), or other significant cardiovascular disease. Uncontrolled hypertension. Hemiplegic or basilar migraine. Use within 24 hours of another 5-HT1 agonist or ergotamine-containing medication. Concurrent use or within 2 weeks of monoamine oxidase inhibitor (MAOI) therapy. Known hypersensitivity to rizatriptan or any component. Severe hepatic impairment (Child-Pugh class C).
| Precautions | Risk of myocardial ischemia and/or infarction, coronary artery vasospasm, cerebrovascular events, and increased blood pressure. Serotonin syndrome (especially when co-administered with other serotonergic drugs). Use only after clear diagnosis of migraine; not for use in hemiplegic or basilar migraine. Caution in patients with risk factors for coronary artery disease. Avoid use within 24 hours of other 5-HT1 agonists or ergotamine derivatives. Monitor for signs/symptoms of serotonin syndrome. |
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| Fetal Monitoring | Monitor for signs of fetal distress if used in late pregnancy due to potential uterine artery vasoconstriction. Also monitor maternal blood pressure and heart rate. Serial ultrasound may be considered if prolonged use or near term. |
| Fertility Effects | No formal studies on human fertility. Animal studies showed no impairment of fertility at doses up to 100 mg/kg/day. Clinical significance unknown. |