SUMATRIPTAN
Clinical safety rating
avoidContraindicated (not allowed)
Selective 5-HT1B/1D receptor agonist; causes vasoconstriction of cranial arteries and inhibits trigeminal nerve transmission.
| Metabolism | Primarily via monoamine oxidase A (MAO-A); minor via cytochrome P450 (CYP) enzymes. |
| Excretion | 60% renal (as indole acetic acid metabolite), 40% fecal; <3% unchanged in urine. |
| Half-life | 2.5 hours (range 1–4 h); clinically relevant for redosing interval of ≥2 h. |
| Protein binding | 14–21%, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 2.0–3.3 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: 15% (due to first-pass metabolism); subcutaneous: 97%; intranasal: 17% (with variability). |
| Onset of Action | Oral: 30–60 min; subcutaneous: 10–15 min; intranasal: 15–30 min. |
| Duration of Action | Oral: up to 24 h; subcutaneous: up to 24 h; intranasal: up to 24 h (pain-free response may be shorter). |
| Molecular Weight | 295.4 |
Sumatriptan is available as oral tablets (25 mg, 50 mg, 100 mg), subcutaneous injection (6 mg/0.5 mL), and nasal spray (5 mg, 20 mg). For acute migraine: oral: 50-100 mg at onset, may repeat after 2 hours (max 200 mg/day). Subcutaneous: 6 mg at onset, may repeat after 1 hour (max 12 mg/24h). Nasal spray: 20 mg in one nostril at onset, may repeat after 2 hours (max 40 mg/day).
| Dosage form | SPRAY |
| Renal impairment | No specific dose adjustment is recommended for renal impairment. However, sumatriptan and its metabolites are excreted renally, and caution is advised in severe renal impairment (CrCl <15 mL/min). No specific GFR-based guidelines are established. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh C). For mild to moderate hepatic impairment (Child-Pugh A or B): oral maximum dose is 50 mg; nasal spray: 5 mg single dose; subcutaneous: no specific adjustment, but caution advised due to reduced clearance. |
| Pediatric use | Not approved for pediatric use <18 years. However, off-label: adolescent (12-17 years): oral 25-100 mg at onset, may repeat after 2 hours (max 200 mg/day). Subcutaneous: 3-6 mg at onset (based on weight, e.g., 0.06 mg/kg). Nasal spray: 5-20 mg at onset. |
| Geriatric use | Limited data in elderly. Start with the lowest effective dose (e.g., oral 25 mg, subcutaneous 3 mg, nasal spray 5 mg). Caution due to potential for cardiovascular risk, hypertension, and reduced hepatic/renal function. Avoid in patients with uncontrolled hypertension or ischemic heart disease. |
| 1st trimester | Limited human data; animal studies show increased risk of fetal anomalies at high doses. Use only if benefit outweighs risk. |
| 2nd trimester | Use with caution; may cause uterine hypertonus and reduced placental blood flow. Limited human data. |
| 3rd trimester | Avoid near term due to risk of uterine hypertonus and potential fetal hypoxia. May prolong labor. |
Clinical note
Other 5-HT1 agonists and MAOIs can have additive effects Contraindicated in ischemic heart disease and uncontrolled hypertension.
| Placental transfer | Crosses the placenta; peak fetal-to-maternal ratio approximately 0.3. Evidence of transfer in human studies. |
| Breastfeeding | Excreted into breast milk in low amounts; acute use is considered compatible with breastfeeding. Avoid repeated doses due to potential for infant exposure. Observe infant for irritability, sedation, or feeding difficulties. |
| Lactation Rating | L2 (Safer). Short-term, single doses are considered safe. Repeated use may lead to higher exposure. |
| Teratogenic Risk | FDA Pregnancy Category C. In first trimester, no increased risk of major congenital malformations from available data; however, animal studies show embryo lethality and increased malformations at high doses. Second and third trimester risks include potential for uterine hypertonus and fetal hypoxia during maternal use for migraine attacks; avoid during third trimester due to risk of premature uterine contractions. |
| Fetal Monitoring | Monitor for signs of serotonin syndrome, hypertension, coronary vasospasm, and uterine hypertonus during administration. Fetal heart rate monitoring recommended during third trimester use due to risk of fetal distress from uterine contractions. |
| Fertility Effects | No human studies on fertility. Animal studies show no impairment of fertility at subtoxic doses. |
■ FDA Black Box Warning
Not recommended for use in patients with risk factors for coronary artery disease (e.g., hypertension, diabetes, smoking) unless a cardiovascular evaluation confirms absence of coronary artery disease.
| Common Effects | Chest pain |
| Serious Effects |
History of ischemic heart disease or coronary artery vasospasmUncontrolled hypertensionHemiplegic or basilar migraineUse within 24 hours of another 5-HT1 agonist or ergotamineSevere hepatic impairment
| Precautions | Risk of myocardial ischemia, infarction, and Prinzmetal's angina, Life-threatening serotonin syndrome with concomitant serotonergic drugs, Elevations in blood pressure, Increased risk of cerebrovascular events, Overuse headache with frequent use |
| Food/Dietary | No significant food interactions. Avoid alcohol during migraine attacks as it can worsen headaches. May be taken with or without food. |
| Clinical Pearls | Sumatriptan is a 5-HT1B/1D receptor agonist used for acute migraine. It is available in oral, nasal, subcutaneous, and rectal formulations. Onset of action is fastest with subcutaneous injection (10-15 minutes). Avoid use within 24 hours of other triptans or ergot alkaloids. Contraindicated in patients with ischemic heart disease, cerebrovascular disease, uncontrolled hypertension, or hemiplegic/basilar migraine. Monitor for serotonin syndrome when combined with SSRIs/SNRIs. |
| Patient Advice | Take sumatriptan at the first sign of migraine headache for best results. · Do not exceed the recommended dose: maximum 100 mg orally or 20 mg intranasally per single dose, with a maximum of 200 mg daily for oral formulations. · Seek emergency medical attention if you experience chest pain, shortness of breath, irregular heartbeat, or signs of stroke. · Avoid driving or operating machinery until you know how sumatriptan affects you, as it may cause dizziness or drowsiness. · Inform your doctor if you have heart disease, high blood pressure, or are pregnant or breastfeeding. |
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