Sumatriptan succinate
Sumatriptan succinate (Imitrex)
Sumatriptan succinate
(soo-mah-TRIP-tan)
Pregnancy Category: C Imitrex

Classification: Antimigraine drug

Action/Kinetics: Selective agonist for a vascular 5-HT₁ receptor subtype (probably 5-HT_1D) located on cranial arteries, on the basilar artery, and the vasculature of the dura mater. Activates the 5-HT₁ receptor, causing vasoconstriction and therefore relief of migraine. Transient increases in BP may be observed. No significant activity at 5-HT₂ or 5-HT₃ receptor subtypes; alpha-1-, alpha-2-, or beta-adrenergic receptors; dopamine-1 or dopamine-2 receptors; muscarinic receptors; or benzodiazepine receptors. Time to peak effect after SC: 12 min after a 6-mg SC dose. t1/2 distribution, after SC: 15 min; terminal t1/2: 115 min. Approximately 22% of a SC dose is excreted in the urine as unchanged drug and 38% as metabolites. Rapidly absorbed after PO administration, although bioavailability is low due to incomplete absorption and a first-pass effect (bioavailability may be significantly increased in those with impaired liver function). PO, elimination t1/2: About 2.5 hr. About 60% of a PO dose is excreted through the urine and 40% in the feces.

Uses: Treatment of acute migraine attacks with or without aura. Photophobia, phonophobia, N&V associated with migraine attacks are also relieved. Intended to relieve migraine, but not to prevent or reduce the number of attacks experienced. Acute treatment of cluster headaches (injection only).

Contraindications: Hypersensitivity to sumatriptan. IV use due to the possibility of coronary vasospasm. SC use in clients with ischemic heart disease, history of MI, documented silent ischemia, Prinzmetal's angina, or uncontrolled hypertension. Concomitant use with ergotamine-containing products or MAO inhibitor therapy (or within 2 weeks of discontinuing an MAO inhibitor). Use in clients with hemiplegic or basilar migraine. Use in women who are pregnant, think they may be pregnant, or are trying to get pregnant.

Special Concerns: Use with caution during lactation, in clients with impaired hepatic or renal function, and in clients with heart conditions. Clients with risk factors for CAD (e.g., men over 40, smokers, postmenopausal women, hypertension, obesity, diabetes, hypercholesterolemia, family history of heart disease) should be screened before initiating treatment. Safety and efficacy have not been determined for use in children.

Side Effects: Side effects listed are for either SC or PO use of the drug. CV: Coronary vasospasm in clients with a history of CAD. Serious and/or life-threatening arrhythmias, including atrial fibrillation, ventricular fibrillation, ventricular tachycardia, MI, marked ischemic ST elevations chest and arm discomfort representing angina pectoris. Flushing, hypertension, hypotension, bradycardia, tachycardia, palpitations, pulsating sensations, ECG changes (including nonspecific ST- or T-wave changes, prolongation of PR or QTc intervals, sinus arrhythmia, nonsustained ventricular premature beats, isolated junctional ectopic beats, atrial ectopic beats, and delayed activation of the right ventricle), syncope, pallor, abnormal pulse, vasodilatation, atherosclerosis, bradycardia, cerebral ischemia, CV lesion, heart block, peripheral cyanosis, thrombosis, transient myocardial ischemia, vasodilation, Raynaud's syndrome. At injection site: Pain, redness. Atypical sensations: Sensation of warmth, cold, tingling, or paresthesia. Localized or generalized feeling of pressure, burning, numbness, and tightness. Feeling of heaviness, feeling strange, tight feeling in head. CNS: Fatigue, dizziness, drowsiness, vertigo, sedation, headache, anxiety, malaise, confusion, euphoria, agitation, relaxation, chills, tremor, shivering, prickling or stinging sensations, phonophobia, depression, euphoria, facial pain, heat sensitivity, incoordination, monoplegia, sleep disturbances, shivering. EENT: Throat discomfort, discomfort in nasal cavity or sinuses. Vision alterations, eye irritation, photophobia, lacrimation, otalgia, feeling of fullness in ear, disorders of sclera, mydriasis. GI: Abdominal discomfort, dysphagia, discomfort of mouth and tongue, gastroesophageal reflux, diarrhea, peptic ulcer, retching, flatulence, eructation, gallstones, taste disturbances, GI bleeding, hematemesis, melena. Respiratory: Dyspnea, diseases of the lower respiratory tract, hiccoughs, influenza, asthma. Dermatologic: Erythema, pruritus, skin rashes, skin eruptions, skin tenderness, dry or scaly skin, tightness or wrinkling of skin. GU: Dysuria, dysmenorrhea, urinary frequency, renal calculus, breast tenderness, increased urination, intermenstrual bleeding, nipple discharge, abortion, hematuria. Musculoskeletal: Weakness, neck pain or stiffness, myalgia, muscle cramps, joint disturbances (pain, stiffness, swelling, ache), muscle stiffness, need to flex calf muscles, backache, muscle tiredness, swelling of the extremities, tetany. Endocrine: Elevated TSH levels, galactorrhea, hyperglycemia, hypoglyclemia, hypothyroidism, weight gain or loss. Miscellaneous: Chest, jaw, or neck tightness. Sweating, thirst, polydipsia, chills, fever, dehydration.

Laboratory Test Alterations: Disturbance of LFTs.

Overdose Mangement: Symptoms: Tremor, convulsions inactivity erythema of extremities, reduced respiratory rate, cyanosis, ataxia, mydriasis, injection site reactions (desquamation, hair loss, scab formation), paralysis. Treatment: Continuous monitoring of client for at least 10 hr and especially when signs and symptoms persist.

Drug Interactions: Ergot drugs / Prolonged vasospastic reactions Monoamine oxidase A inhibitors / t1/2 of sumatriptan Selective Serotonin Reuptake Inhibitors (SSRIs) / Rarely, weakness, hyperreflexia, and incoordination

How Supplied: Injection: 6 mg/0.5 mL; Kit: 6 mg/0.5 mL; Nasal spray: 5 mg, 20 mg; Tablet: 25 mg, 50 mg

Dosage
•SC Migraine headaches.
Adults: 6 mg. A second injection may be given if symptoms of migraine come back but no more than two injections (6 mg each) should be taken in a 24-hr period and at least 1 hr should elapse between doses.
•Tablets
Adults: 25 mg with fluids as soon as symptoms of migraine appear. A second dose may be taken if symptoms return but not sooner than 2 hr following the first dose. Maximum recommended dose: 100 mg, with no more than 300 mg taken in a 24-hr period.
•Nasal Spray
A single dose of 5, 10, or 20 mg given in one nostril. The 20 mg dose increases the risk of side effects. The 10-mg dose may be given as a single 5-mg dose in each nostril. If the headache returns, repeat the dose once after 2 hr; not to exceed a total daily dose of 40 mg. The safety of treating an average of more than 4 headaches in a 30-day period has not been studied.