Imitrex Tablets

— THERAPEUTIC CATEGORIES —
  • Migraine and headache
PAGE CONTENTS
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  • Generic Name & Formulations
  • Indications
  • Dosage and Administration
  • Contraindications
  • Boxed Warnings
  • Warnings/Precautions
  • Pharmacokinetics
  • Interactions
  • Adverse Reactions
  • Clinical Trials
  • Note
  • Patient Counseling

    • Imitrex Tablets Generic Name & Formulations

    Legal Class

    Rx

    General Description

    Sumatriptan (as succinate) 25mg, 50mg, 100mg.

    Pharmacological Class

    Selective 5-HT1B/1D receptor agonist.

    See Also

    How Supplied

    STATdose kit (2 prefilled cartridges + 1 Pen)—1; Refills (2 prefilled cartridges)—1; Single-dose vials (6mg/0.5mL)—5; Tabs—9; Nasal spray (single dose)—6

    How Supplied

    Imitrex Tablets

    • 25mg – white, triangular-shaped, film-coated tablets debossed with “I” on one side and “25” on the other in blister packs of 9 tablets.

    • 50mg – white, triangular-shaped, film-coated tablets debossed with “IMITREX 50” on one side and a chevron shape (^) on the other in blister packs of 9 tablets.

    • 100mg – 100 mg, are pink, triangular-shaped, film-coated tablets debossed with “IMITREX 100” on one side and a chevron shape (^) on the other in blister packs of 9 tablets.

    Storage

    Imitrex Tablets – Store between 2°C and 30°C (36°F and 86°F). 

    Manufacturer

    GlaxoSmithKline

    Mechanism of Action

    The vascular 5-HT1 receptor subtype to which sumatriptan binds selectively, and through which it presumably exerts its antimigrainous effect, is present on cranial arteries in both dog and primate, on the human basilar artery, and in the vasculature of the isolated dura mater of humans. In these tissues, sumatriptan activates this receptor to cause vasoconstriction, an action in humans correlating with the relief of migraine and cluster headache.

    Imitrex Tablets Indications

    Indications

    Acute treatment of migraine.

    Limitations of Use

    Confirm diagnosis of migraine or cluster headache. Do not use for the prevention of migraine or cluster headache attacks.

    Imitrex Tablets Dosage and Administration

    Adult

    ≥18yrs: 25–100mg once, swallow whole with fluids as soon as possible after migraine onset; may repeat dose at intervals of at least 2hrs, max 200mg/day; or single-dose tablets up to 100mg/day if injection has been used. Hepatic dysfunction: max 50mg/dose. The safety of treating an average of more than 4 headaches in a 30-day period has not been established.

    Children

    <18yrs: not recommended.

    Imitrex Tablets Contraindications

    Contraindications

    Ischemic coronary artery disease (eg, angina pectoris, silent ischemia, history of MI). Coronary artery vasospasm (eg, Prinzmetal's variant angina). Wolff-Parkinson-White Syndrome or arrhythmias associated with other cardiac conduction pathway disorders. Uncontrolled hypertension. History of stroke or transient ischemic attack (TIA). History of basilar or hemiplegic migraine. Peripheral vascular disease. Ischemic bowel disease. Severe hepatic impairment. Within 24 hours of ergot-type drugs (eg, methysergide, dihydroergotamine), or other 5-HT1 agonists. During or within 2 weeks after discontinuing MAO-A inhibitors (MAOI type A).

    Imitrex Tablets Boxed Warnings

    Not Applicable

    Imitrex Tablets Warnings/Precautions

    Warnings/Precautions

    Confirm diagnosis. Avoid excessive use. Exclude underlying cardiovascular disease, supervise 1st dose, and consider monitoring ECG in patients with likelihood of unrecognized coronary artery disease (eg, postmenopausal women, hypercholesterolemia, men over age 40, hypertension, obesity, diabetes, smokers, strong family history). Monitor cardiovascular function in long-term intermittent use. Peripheral vascular or colonic ischemia following other 5-HT1 agonists. Hepatic or renal dysfunction. Seizure risk. Latex allergy (Inj). Instruct patient on use of autoinjector. Elderly: not recommended. Pregnancy. Nursing mothers (avoid nursing for 12 hours after treatment).

    Warnings/Precautions

    Myocardial Ischemia, Myocardial Infarction, and Prinzmetal Angina

    • Imitrex is contraindicated in patients with ischemic or vasospastic coronary artery disease (CAD). Rare reports of serious cardiac adverse reactions, including acute myocardial infarction, have occurred within a few hours following administration.

    • Prior to treatment, perform a cardiovascular evaluation in triptan-naïve patients who have multiple cardiovascular risk factors (eg, increased age, diabetes, hypertension, smoking, obesity, strong family history of CAD). Do not administer if there is evidence of CAD or coronary artery vasospasm (see Contraindications). For patients with multiple cardiovascular risk factors who have a negative cardiovascular evaluation, consider administering the first Imitrex dose in a medically-supervised setting and performing an electrocardiogram (ECG) immediately following administration and consider periodic cardiovascular evaluation in intermittent long-term users of Imitrex Injection. 

    Arrhythmias

    • Life-threatening disturbances of cardiac rhythm including ventricular tachycardia and ventricular fibrillation leading to death have been reported within a few hours following the administration of 5-HT1 agonists. Discontinue Imitrex if these disturbances occur. 

    • Imitrex is contraindicated in patients with Wolff-Parkinson-White Syndrome or arrhythmias associated with other cardiac accessory conduction pathway disorders.

    Chest, Throat, Neck and Jaw Pain/Tightness/Pressure

    • Perform a cardiac evaluation if patients who are at high cardiac risk experience sensations of tightness, pain, and pressure in the chest, throat, neck, and jaw after treatment with Imitrex. 

    • Imitrex is contraindicated in patients with CAD or Prinzmetal’s variant angina.

    Cerebrovascular Events

    • Cerebral hemorrhage, subarachnoid hemorrhage, and stroke have occurred in patients treated with 5-HT1 agonists, and some have resulted in fatalities. 

    • Exclude other potentially serious neurological conditions before treating headaches in patients not previously diagnosed as migraineurs, and in migraineurs who present with symptoms atypical for migraine. 

    • Discontinue Imitrex if a cerebrovascular event occurs. Imitrex is contraindicated in patients with a history of stroke or transient ischemic attack.

    Other Vasospasm Reactions

    • May cause non-coronary vasospastic reactions, such as peripheral vascular ischemia, gastrointestinal vascular ischemia and infarction (presenting with abdominal pain and bloody diarrhea), splenic infarction, and Raynaud’s syndrome. 

    • Rule out a vasospastic reaction before receiving additional doses of Imitrex in patients who experience symptoms or signs suggestive of a non-coronary vasospastic reaction following the use of any 5-HT1 agonist.

    • Reports of transient and permanent blindness and significant partial vision loss have been reported with the use of 5-HT1 agonists. A causal relationship between visual  disorders and the use of 5-HT1 agonists has not been clearly established. 

    Medication Overuse Headache

    • Overuse of acute migraine drugs (eg, ergotamine, triptans, opioids, or a combination of drugs for 10 or more days per month) may lead to exacerbation of headache (medication overuse headache).

    • Medication overuse headache may present as migraine-like daily headaches or as a marked increase in frequency of migraine attacks. 

    • May be necessary to detoxify patients, including withdrawal of the overused drugs, and treatment of withdrawal symptoms (which often includes a transient worsening of headache). 

    Serotonin Syndrome

    • May occur when Imitrex is coadministered with SSRIs, SNRIs, TCAs, and MAO inhibitors.

    • The onset of symptoms usually rapidly occurs within minutes to hours of receiving a new or a greater dose of a serotonergic medication. 

    • Discontinue if serotonin syndrome is suspected.

    Increase in Blood Pressure

    • Significant elevations in blood pressure, including hypertensive crisis with acute impairment of organ systems, have been reported in patients treated with 5-HT1 agonists including patients without a history of hypertension. 

    • Monitor blood pressure. Imitrex is contraindicated in patients with uncontrolled hypertension.

    Anaphylactic/Anaphylactoid Reactions

    • Hypersensitivity reactions, including angioedema and anaphylaxis, have occurred which may be life-threatening or fatal.

    • Imitrex is contraindicated in patients with a history of hypersensitivity reaction to Imitrex.

    Seizures

    • Use caution in patients with a history of epilepsy or conditions associated with a lowered seizure threshold.

    Pregnancy Considerations

    Risk Summary

    • Data from a prospective pregnancy exposure registry and epidemiological studies of pregnant women have not detected an increased frequency of birth defects or a consistent pattern of birth defects among women exposed to sumatriptan compared with the general population. 

    Clinical Considerations

    • Women with migraine may be at increased risk of preeclampsia during pregnancy.

    Nursing Mother Considerations

    Risk Summary

    • There are no data on the effects of sumatriptan on the breastfed infant, or the effects of sumatriptan on milk production. 

    • Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for Imitrex and any potential adverse effects on the breastfed infant from sumatriptan or from the underlying maternal condition.

    Clinical Considerations

    • Avoid breastfeeding for 12 hours after treatment with Imitrex.

    Pediatric Considerations

    Safety and effectiveness in pediatric patients have not been established. Imitrex is not recommended for use in patients younger than 18 years of age.

    Geriatric Considerations

    • Clinical trials of Imitrex did not include sufficient numbers of patients aged 65 years and older to determine whether they respond differently from younger patients.  In general, use caution with dose selection for an elderly patient, usually starting at the low end of the dosing range.

    • Perform cardiovascular evaluation for geriatric patients who have other cardiovascular risk factors (eg, diabetes, hypertension, smoking, obesity, strong family history of CAD) prior to receiving Imitrex.

    Imitrex Tablets Pharmacokinetics

    Absorption

    The mean maximum concentration following oral dosing with 25 mg is 18 ng/mL (range: 7 to 47 ng/mL) and 51 ng/mL (range: 28 to 100 ng/mL) following oral dosing with 100 mg of sumatriptan. This compares with a Cmax of 5 and 16 ng/mL following dosing with a 5- and 20-mg intranasal dose, respectively. The bioavailability is approximately 15%, primarily due to presystemic metabolism and partly due to incomplete absorption. 

    Effect of Food: A food effect trial involving administration of Imitrex tablets 100 mg to healthy volunteers under fasting conditions and with a high-fat meal indicated that the Cmax and AUC were increased by 15% and 12%, respectively, when administered in the fed state.  

    Distribution

    Protein binding, determined by equilibrium dialysis over the concentration range of 10 to 1,000 ng/mL is low, approximately 14% to 21%. The effect of sumatriptan on the protein binding of other drugs has not been evaluated. The apparent volume of distribution is 2.7 L/kg.

    Metabolism

    In vitro studies with human microsomes suggest that sumatriptan is metabolized by MAO, predominantly the A isoenzyme. Most of a radiolabeled dose of sumatriptan excreted in the urine is the major metabolite indole acetic acid (IAA) or the IAA glucuronide, both of which are inactive.

    Elimination

    The elimination half-life of sumatriptan is approximately 2.5 hours. Radiolabeled 14Csumatriptan administered orally is largely renally excreted (about 60%) with about 40% found in the feces.

    Imitrex Tablets Interactions

    Interactions

    Ergotamines, other 5-HT1 agonists, MAOIs: see Contraindications. Serotonin syndrome with SSRIs (eg, citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline) or SNRIs (eg, duloxetine, venlafaxine).

    Imitrex Tablets Adverse Reactions

    Adverse Reactions

    Tingling, warm/hot sensation, flushing; chest/neck/sinus/jaw discomfort; dizziness/vertigo, muscle pain/weakness, numbness, fatigue, drowsiness, anxiety, sweating, local reactions, seizures, colonic ischemia, drug overuse headache (discontinue if occurs), hypersensitivity reactions; rare: serious cardiac and cerebrovascular events (including fatalities), vision loss. Nasal spray: also dysgeusia, local irritation.

    Imitrex Tablets Clinical Trials

    Clinical Trials

    • Imitrex Tablets was evaluated for the acute treatment of migraine headaches in 3 randomized, double-blind, placebo-controlled trials. Patients were instructed to treat a moderate to severe headache. Patients were allowed to take a second dose of Imitrex tablets or other medication 4 to 24 hours after the initial treatment for recurrent headache.

    • Headache response was defined as a reduction in headache severity from moderate to severe pain to mild or no pain and was assessed up to 2 hours after dosing. Maintenance of response was assessed for up to 24 hours post-dose.

    • In all 5 trials, a greater percentage of patients treated with Imitrex 25mg, 50mg, and 100mg achieved headache response (no or mild pain) at 2 and 4 hours post-dose compared with placebo.

      • Trial 1

        • Imitrex 25mg: 52%a at 2hrs and 67%a at 4hrs

        • Imitrex 50mg: 61%a,b at 2hrs and 78%a,b at 4hrs

        • Imitrex 100mg: 62%a,b at 2hrs and 79%a,b at 4hrs

        • Placebo: 27% at 2hrs and 38% at 4hrs

        • a P <.05 in comparison with placebo; b P <.05 in comparison with 25mg

      • Trial 2

        • Imitrex 25mg: 52%a at 2hrs and 70%a at 4hrs

        • Imitrex 50mg: 50%a at 2hrs and 68%a at 4hrs

        • Imitrex 100mg: 56%a at 2hrs and 71%a at 4hrs

        • Placebo: 26% at 2hrs and 38% at 4hrs

        • a P <.05 in comparison with placebo; b P <.05 in comparison with 25mg

      • Trial 3

        • Imitrex 25mg: 52%a at 2hrs and 65%a at 4hrs

        • Imitrex 50mg: 54%a at 2hrs and 72%a at 4hrs

        • Imitrex 100mg: 57%a at 2hrs and 78%a at 4hrs

        • Placebo: 17% at 2hrs and 19% at 4hrs

        • a P <.05 in comparison with placebo; b P <.05 in comparison with 25mg

    • Patients treated with Imitrex nasal spray had a lower incidence of photophobia, phonophobia, nausea and vomiting associated with migraine attacks.

    Imitrex Tablets Note

    Notes

    Register pregnant patients exposed to sumatriptan by calling (800) 336-2176.

    Imitrex Tablets Patient Counseling

    Patient Counseling

    Risk of Myocardial Ischemia and/or Infarction, Prinzmetal’s Angina, Other Vasospastic Reactions, and Cerebrovascular Events 

    • Inform patients that Imitrex Injection may cause serious cardiovascular adverse reactions such as myocardial infarction or stroke, which may result in hospitalization and even death. Instruct patients to be alert for the signs and symptoms of chest pain, shortness of breath, weakness, slurring of speech, and instruct them to ask for medical advice when observing any indicative sign or symptoms; serious cardiovascular reactions may occur without warning symptoms. Instruct patients to seek medical advice if they have symptoms of other vasospastic reactions.

    Hypersensitivity Reactions

    • Anaphylactic reactions have occurred in patients receiving Imitrex Injection. Instruct patients to seek immediate medical attention if anaphylactic symptoms develop.

    Concomitant Use with Other Triptans or Ergot Medications

    • Inform patients that use of Imitrex Injeciton within 24 hours of another triptan or an ergot-type medication (eg, dihydroergotamine or methysergide) is contraindicated.

    Serotonin Syndrome

    • Inform patients about the risk of serotonin syndrome with the use of Imitrex Injection or other triptans, particularly during combined use with SSRIs, SNRIs, TCAs, and MAO inhibitors.

    Medication Overuse Headache

    • Inform patients that use of drugs to treat acute migraines for 10 or more days per month may lead to an exacerbation of headache, and encourage patients to record headache frequency and drug use (e.g., by keeping a headache diary). 

    Pregnancy 

    • Advise patients to notify their healthcare provider if they are pregnant or plan to become pregnant.

    Lactation 

    • Advise patients to notify their healthcare provider if they are breastfeeding or plan to breastfeed.

    Ability to Perform Complex Tasks

    • Imitrex Injection may cause somnolence and dizziness. Instruct patients to evaluate their ability to perform complete tasks after administration.

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