RIZATRIPTAN BENZOATE
Clinical safety rating
avoidContraindicated (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. |
| Molecular Weight | 391.47 |
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 | Limited human data; animal studies show no teratogenicity at clinically relevant doses. Use only if potential benefit justifies risk. |
| 2nd trimester | No known increased risk of malformations; monitor for potential maternal adverse effects such as hypertension and serotonin syndrome. |
| 3rd trimester | Risk of neonatal withdrawal (irritability, hypotonia) if used near term. Avoid close to delivery due to potential uterine hypertonicity. |
Clinical note
MAOIs and other 5-HT1 agonists can have additive effects Contraindicated in ischemic heart disease and uncontrolled hypertension.
| Placental transfer | Rizatriptan crosses the placenta; fetal plasma concentrations reach approximately 15% of maternal levels. |
| Breastfeeding | Rizatriptan is excreted into human breast milk in low amounts (<14% of maternal weight-adjusted dose). No adverse effects reported in exposed infants. Use with caution, preferably after nursing to minimize infant exposure. |
| Lactation Rating | L2 (Safer) |
| 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. |
| 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. |
■ FDA Black Box Warning
None
| Common Effects | Dizziness |
| Serious Effects |
History of ischemic heart diseaseCoronary artery vasospasm (e.g., Prinzmetal's angina)Uncontrolled hypertensionHemiplegic or basilar migraineIschemic bowel diseaseConcurrent use of MAO inhibitors or within 2 weeks of discontinuationSevere hepatic impairment
| 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. |
| Food/Dietary | No significant food interactions. However, high-fat meals may delay absorption. Avoid alcohol as it may worsen headaches or increase side effects. |
| Clinical Pearls | Rizatriptan is a selective 5-HT1B/1D receptor agonist used for acute migraine. Onset of action is rapid (30 min). Maximum daily dose is 30 mg (oral tablets) or 30 mg (ODT). Do not use within 24 hours of other triptans or ergotamines. Contraindicated in patients with ischemic heart disease, uncontrolled hypertension, or basilar/hemiplegic migraine. Avoid in patients with moderate/severe hepatic impairment. ODT dissolves quickly and can be taken without water, useful for patients with nausea. |
| Patient Advice | Take at the first sign of migraine headache; it will not prevent attacks. · Do not exceed 30 mg in any 24-hour period (separate doses by at least 2 hours). · If first dose does not work, do not take a second dose for the same attack without consulting your doctor. · Seek emergency care if you experience chest pain, shortness of breath, or sudden severe headache. · Inform your doctor if you have heart disease, high blood pressure, or are taking MAOIs (within 2 weeks) or other migraine medications. |
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