ZOMIG-ZMT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZOMIG-ZMT (ZOMIG-ZMT).
Selective serotonin 5-HT1B/1D receptor agonist; causes vasoconstriction of cranial blood vessels, inhibits trigeminal nerve transmission, and reduces neurogenic inflammation.
| Metabolism | Hepatic metabolism primarily via CYP1A2 to active N-desmethylzolmitriptan; minor metabolism by CYP3A4 and monoamine oxidase A (MAO-A). |
| Excretion | Approximately 60-70% of the administered dose is excreted in urine, primarily as metabolites (active N-desmethyl zolmitriptan and inactive indoleacetic acid derivatives), with about 10-15% as unchanged drug. Fecal excretion accounts for about 20-30% of the dose. |
| Half-life | Terminal elimination half-life is approximately 3 to 3.5 hours for zolmitriptan and its active metabolite N-desmethyl zolmitriptan has a similar half-life. This supports a typical dosing interval of at least 2 hours between doses. |
| Protein binding | Approximately 25% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is about 2.4 L/kg, indicating extensive tissue distribution beyond plasma water. |
| Bioavailability | Oral bioavailability of zolmitriptan is approximately 40-50% due to first-pass metabolism. The orally disintegrating tablet has similar bioavailability to conventional tablets. Subcutaneous administration yields near 100% bioavailability. |
| Onset of Action | Orally disintegrating tablet: Onset of headache relief occurs within 30 minutes in some patients, with maximal effect at 2-4 hours. Subcutaneous injection (Zomig formulation): onset in 10-15 minutes. |
| Duration of Action | Duration of clinical effect (headache relief) is approximately 4-6 hours. Recurrence of headache within 24 hours may occur in some patients, necessitating a second dose after 2 hours. |
2.5 mg orally at onset of migraine; may repeat after 2 hours if needed. Maximum 10 mg in 24 hours.
| Dosage form | TABLET, ORALLY DISINTEGRATING |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment. Use with caution in severe renal impairment (CrCl <15 mL/min) due to limited data. |
| Liver impairment | Child-Pugh Class A: No adjustment. Child-Pugh Class B: 2.5 mg orally at onset; maximum 5 mg in 24 hours. Child-Pugh Class C: Not recommended. |
| Pediatric use | Children ≥12 years: 2.5 mg orally at onset of migraine; may repeat after 2 hours if needed. Maximum 5 mg in 24 hours. Children <12 years: Safety and efficacy not established. |
| Geriatric use | No specific dosage adjustment but use with caution due to potential for reduced hepatic or renal function and increased sensitivity; initiate at lowest dose. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ZOMIG-ZMT (ZOMIG-ZMT).
| Breastfeeding | Unknown if excreted in human milk. Low molecular weight suggests possible transfer. M/P ratio not established. Caution advised; consider alternative therapies or discontinue breastfeeding. |
| Teratogenic Risk | Pregnancy Category C. First trimester: Limited human data; animal studies show embryotoxicity and fetal abnormalities at doses below human therapeutic exposure. Second/third trimester: No adequate human studies; potential for uteroplacental ischemia due to vasoconstriction. Avoid use unless potential benefit justifies risk. |
■ FDA Black Box Warning
None
| Serious Effects |
["Ischemic heart disease","History of myocardial infarction","Coronary artery vasospasm (Prinzmetal's angina)","Uncontrolled hypertension","Hemiplegic or basilar migraine","Concurrent use of MAO inhibitors or within 2 weeks of discontinuation","Severe hepatic impairment (Child-Pugh C)","Hypersensitivity to zolmitriptan or any component of the formulation"]
| Precautions | ["Serotonin syndrome (especially with SSRIs/SNRIs)","Coronary artery vasospasm/ischemia in patients with risk factors","Hypertension","Cerebral hemorrhage/stroke","Cardiac arrhythmias","Medication-overuse headache","Severe hepatic impairment: contraindicated"] |
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| Fetal Monitoring |
| Monitor maternal blood pressure and heart rate. Assess fetal heart rate patterns if used near term due to potential for uteroplacental insufficiency. Observe for signs of maternal serotonin syndrome if co-administered with other serotonergic drugs. |
| Fertility Effects | No human studies. In animal studies, no adverse effects on fertility at sub-maternally toxic doses. Theoretical risk due to 5-HT1B/1D receptor agonism on reproductive tissues; clinical significance unknown. |