SUMATRIPTAN

(sum-a-trip'tan)

Imitrex
Classifications: serotonin 5-ht₁ agonist;
Therapeutic: antimigraine; 5-ht₁-serotonin agonist
Pregnancy Category: C

Availability

25 mg, 50 mg tablets; 12 mg/mL injection; 5 mg, 20 mg nasal spray

Action

Selective agonist for a serotonin receptor (probably 5-HT_1D) that causes vasoconstriction of cranial carotid arteries.

Therapeutic Effect

Causes vasoconstriction of cranial carotid arteries, thus relieving the migraine headache. Also relieves photophobia, phonophobia, nausea and vomiting associated with migraine attacks.

Uses

Treatment of acute migraine attacks with or without aura, cluster headache.

Contraindications

Hypersensitivity to sumatriptan; IV use; coronary artery disease (CAD); acute MI, angina, arteriosclerosis; cerebrovascular disease; colitis; older adults; risk factors for CAD such as hypertension, hypercholesterolemia, obesity, diabetes, smoking, and strong family history; concurrent use with ergotamine drugs; concurrent use of oral sumatriptan with MAO inhibitors; intracranial bleeding; PVD; Raynaud's disease; stroke; Wolff-Parkinson-White syndrome; basilar or hemiplegic migraine; pregnancy (category C).

Cautious Use

Impaired liver or kidney function; concurrent use of subcutaneous sumatriptan and MAO inhibitors. Safety and effectiveness in children are not established.

Route & Dosage

Migraine or Cluster Headache
Adult: SC 6 mg any time after onset of migraine. If headache returns, may repeat with 6 mg SC at least 1 h after first injection (max: 12 mg/24 h). PO 25 mg x 1 dose, if headache returns may repeat once after 2 h (max: 100 mg). Intranasal 5, 10, or 20 mg in one nostril. If headache returns, may repeat once after 2 h (max: 40 mg/24 h).

Administration

Note: Do not give within 24 h of an ergot-containing drug.

Oral

Give any time after symptoms of migraine appear.
A second tablet may be given if symptoms return but no sooner than 2 h after the first tablet.
Do not exceed 100 mg in a single oral dose or 300 mg/d.

Intranasal

Note: A single dose is one spray into ONE nostril.

Subcutaneous

A second injection may be given 1 h or longer following first injection if initial relief is not obtained or if migraine returns.
Be aware that if adverse effects are dose limiting, a lower dose may be effective.
Store all forms at room temperature, 15°–30° C (59°–86° F). Protect from light.

Adverse Effects (≥1%)

CV: Chest pressure and tightness, hypotension or hypertension, hypertensive crisis, syncope, peripheral cyanosis, thromboembolism, heart block, sinus bradycardia, atrial fibrillation, ventricular fibrillation, ventricular tachycardia, coronary artery vasospasm, angina, transient myocardial ischemia, MI, cardiac arrest. CNS: Tingling, warming sensation, pressure, numbness, headache, dizziness, vertigo, drowsiness, sedation, seizure, CNS hemorrhage, subarachnoid hemorrhage, stroke. Body as a Whole: Dizziness, lightheadedness, myalgia, or muscle cramps, pain on injection, weakness, flushing and a sensation of warmth or burning after injection. GI: Abdominal pain, cramping, diarrhea, nausea, vomiting.

Interactions

Drug: Dihydroergotamine, ergot alkaloids may cause vasospasm and a slight elevation in blood pressure. mao inhibitors increase sumatriptan levels and toxicity (especially the oral form); do not use concurrently or within 2 wk of stopping mao inhibitors; use with other serotonin altering drugs increases risk of serotonin syndrome (see Appendix F). Herbal: St. John's wort may increase triptan toxicity.

Pharmacokinetics

Onset: 10–30 min after SC administration. Duration: 1–2 h. Distribution: Widely distributed, 10–20% protein bound. May be excreted in breast milk. Metabolism: Hepatically to inactive metabolite. Elimination: 57% in urine, 38% in feces. Half-Life: 2 h.

Nursing Implications

Assessment & Drug Effects

Monitor cardiovascular status carefully following first dose in patients at relatively high risk for coronary artery disease (e.g., postmenopausal women, men over 40 years old, persons with known CAD risk factors) or who have coronary artery vasospasms.
Report to physician immediately chest pain or tightness in chest or throat that is severe or does not quickly resolve following a dose of sumatriptan.
Monitor therapeutic effectiveness. Pain relief usually begins within 10 min of injection, with complete relief in approximately 65% of all patients within 2 h.

Patient & Family Education

Review patient information leaflet provided by the manufacturer carefully.
Learn correct use of autoinjector for self-administration of SC dose.
Pain or redness at injection site is common but usually disappears in less than 1 h.
Notify physician immediately if symptoms of severe angina (e.g., severe or persistent pain or tightness in chest, back, neck, or throat) or hypersensitivity (e.g., wheezing, facial swelling, skin rash, or hives) occur.
Do not take any other serotonin receptor agonist (Axert, Maxalt, Zomig, Amerge) within 24 h of taking sumatriptan.
Check with physician before taking any new OTC or prescription drugs.
Report any other adverse effects (e.g., tingling, flushing, dizziness) at next physician visit.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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