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. |
| Molecular Weight | 287.36 |
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 | Limited human data; animal studies show fetal harm at high doses. Avoid use unless potential benefit outweighs risk. |
| 2nd trimester | Limited human data; consider risk of reduced uteroplacental blood flow due to vasoconstriction. |
| 3rd trimester | Avoid use; may cause uterine contractions and reduced placental perfusion. |
Clinical note
Comprehensive clinical and safety monograph for ZOMIG-ZMT (ZOMIG-ZMT).
| Placental transfer | Zolmitriptan crosses the placenta in rats; limited human data suggest placental transfer occurs. The degree of transfer in humans is not well quantified but is expected to be low due to molecular properties. |
| Breastfeeding | Zolmitriptan is excreted into human breast milk in low concentrations. The relative infant dose is approximately 3-4% of the maternal dose. Due to the potential for adverse effects (e.g., vasospasm, adverse CNS effects) in nursing infants, caution is advised. Consider postponing breastfeeding for at least 4-6 hours after a dose. |
■ FDA Black Box Warning
None
| Serious Effects |
History of ischemic heart disease or coronary artery vasospasm (e.g., Prinzmetal's angina)Uncontrolled hypertensionHemiplegic or basilar migraineConcurrent use of MAO-A inhibitors or within 2 weeks of discontinuationSevere hepatic impairment (Child-Pugh C)
| 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 |
| Food/Dietary | No specific food interactions reported. Grapefruit and grapefruit juice may increase zolmitriptan levels; avoid concurrent consumption. |
Loading safety data…
| Lactation Rating | L3 (Moderately Safe) |
| 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. |
| 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. |
| Clinical Pearls | ZOMIG-ZMT (zolmitriptan) is an orally disintegrating tablet for acute migraine treatment that dissolves on the tongue without water, useful for patients with nausea/vomiting. Onset of action is within 30-60 minutes. Contraindicated in patients with history of ischemic heart disease, coronary artery vasospasm (including Prinzmetal angina), cerebrovascular syndromes, or uncontrolled hypertension. Do not use within 24 hours of other 5-HT1 agonists or ergotamines. Maximum dose is 10 mg in 24 hours. The 5 mg dose may be more effective than 2.5 mg in some patients, but 2.5 mg is the recommended starting dose. |
| Patient Advice | Take ZOMIG-ZMT at the first sign of a migraine headache; it is not for prevention. · Place the tablet on your tongue where it will dissolve quickly; no water needed. · Do not take more than one dose within 2 hours, and do not exceed 10 mg in 24 hours. · Do not take ZOMIG-ZMT if you have taken another triptan or ergotamine in the last 24 hours. · Seek emergency care if you experience chest pain, shortness of breath, irregular heartbeat, or sudden severe abdominal pain. · Tell your doctor if you have risk factors for heart disease (e.g., high blood pressure, diabetes, smoking, high cholesterol, family history). · Do not use if you have uncontrolled high blood pressure, had a stroke or transient ischemic attack, or have peripheral vascular disease. |