sumatriptan
Brand: Imitrex, Tosymra, Zembrace
Prototype Drug
Drug Class: antimigraine
Drug Family: antimigraine
Subclass: triptan / serotonin 5-HT1B/1D agonist
Organ Systems: cns
Mechanism of Action
Selective agonist at 5-HT1B (causing vasoconstriction of dilated intracranial vessels) and 5-HT1D receptors (inhibiting trigeminal nerve activation and substance P release); directly targets the pathophysiology of migraine at both the vascular and neural levels.
serotonin 5-HT1B receptorsserotonin 5-HT1D receptors
Indications
- acute migraine with or without aura
- cluster headache (SC formulation)
Contraindications
- coronary artery disease or history of MI
- uncontrolled hypertension
- cerebrovascular disease
- hemiplegic or basilar migraine
- concurrent ergotamine/DHE
- within 24 hours of another triptan
Adverse Effects
Common
- chest tightness/pressure (non-cardiac in most cases)
- paresthesias
- warm/tingling sensation
- neck stiffness
- nausea (injection site: stinging)
Serious
- coronary vasospasm / MI (rare but serious)
- serotonin syndrome (with SSRIs/SNRIs)
- peripheral vascular ischemia
- medication overuse headache with frequent use
Pharmacokinetics (ADME)
| Absorption | SC: ~96% bioavailability; oral: ~14–15% (significant first-pass); nasal: ~17% |
| Distribution | Protein binding 14–21%; Vd ~170 L |
| Metabolism | MAO-A to inactive indole acetic acid; avoid non-selective MAOIs |
| Excretion | Renal (~60%) and fecal |
| Half-life | 2 hours |
| Onset | SC: 10 minutes; oral: 30 minutes; nasal: 15 minutes |
| Peak | SC: 12 min; oral: 2 hours; nasal: 90 min |
| Duration | 4–6 hours |
| Protein Binding | 14–21% |
| Vd | ~170 L |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| MAOIs | inhibit MAO-A metabolism of sumatriptan; increase sumatriptan levels; potential serotonin syndrome | major |
| ergotamine/DHE | additive vasospasm — do not use within 24 hours of each other | major |
| SSRIs/SNRIs | serotonin syndrome risk (controversial; FDA warning) | moderate |
Nursing Considerations
- Administer at onset of migraine — not as preventive therapy; maximum 2 doses in 24 hours; instruct patient to seek emergency care if chest pain, shortness of breath, or vision changes occur after dose
- Screen for cardiovascular risk factors before prescribing; first dose in patients with cardiovascular risk factors should be administered in medical setting with monitoring
- Medication overuse headache (MOH) develops with use >2–3 days per week; counsel patients to track headache days and limit triptan use
- Autoinjector (Imitrex STATdose): inject into outer thigh or upper arm; avoid deltoid; demonstrate technique and have patient return-demonstrate
Clinical Pearls
- Sumatriptan's oral bioavailability is only 14% due to extensive first-pass metabolism — the subcutaneous formulation provides much faster onset and higher bioavailability but is less commonly used due to injection discomfort
- Triptans are contraindicated in hemiplegic and basilar migraine (uncommon migraine variants) because 5-HT1B-mediated vasoconstriction in the posterior circulation could worsen these aura variants
Safety Profile
Pregnancy avoid
Lactation use-with-caution
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.