What is Imitrex (sumatriptan)?

Imitrex (sumatriptan) is a selective serotonin receptor agonist (a “triptan”) used to treat migraine headaches. Migraine headaches are believed to result from dilatation of blood vessels in the brain. Imitrex relieves migraines by stimulating serotonin receptors in the brain which cause the muscles surrounding the blood vessels in the brain to contract and narrow the blood vessels. At the same time, it also reduces transmission of pain signals by nerves to the brain. Imitrex does not prevent or reduce the number of headaches.

Common side effects of Imitrex include:

Serious side effects of Imitrex are rare and include:

Drug interactions of Imitrex include monoamine oxidase inhibitors (MAOIs), which may reduce the breakdown of Imitrex in the liver leading to increased blood levels and side effects of Imitrex. 

Combining Imitrex with sibutramine, selective serotonin reuptake inhibitors (SSRIs), or serotonin and norepinephrine reuptake inhibitors (SNRIs) may increase the concentration of serotonin in the brain, causing increased serotonin-related side effects. 

Administering Imitrex within 24 hours of treatment with an ergot-containing medication is contraindicated because such combinations increase the likelihood of vasospasms. 

Safe use of Imitrex in pregnancy has not been established. Imitrex is excreted in breast milk. Infant exposure may be reduced by avoiding breastfeeding for 12 hours after administration of Imitrex.

What are the important side effects of Imitrex (sumatriptan)?

Side effects are generally transient. Some common side effects of sumatriptan:

  • pain or tightness in the chest or throat,
  • tingling,
  • flushing,
  • weakness,
  • dizziness,
  • abdominal discomfort,
  • sweating,
  • nasal irritation, and
  • injection site reactions.

Rarely, allergic reactions have been reported, usually in individuals who are highly allergic to multiple allergens. Sumatriptan may elevate blood pressure in individuals with or without a history of high blood pressure. Individuals with uncontrolled high blood pressure should not use sumatriptan.

Other important, but rare, side effects associated with sumatriptan include:

Imitrex (sumatriptan) side effects list for healthcare professionals

The following serious adverse reactions are described below and elsewhere in the labeling:

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Migraine Headache

Table 1 lists adverse reactions that occurred in 2 US placebo-controlled clinical trials in migraine patients (Studies 2 and 3) following either a single 6-mg dose of Imitrex Injection or placebo. Only reactions that occurred at a frequency of 2% or more in groups treated with Imitrex Injection 6 mg and that occurred at a frequency greater than the placebo group are included in Table 1.

Table 1. Adverse Reactions in Pooled Placebo-Controlled Trials in Patients with Migraine (Studies 2 and 3)

  Imitrex Injection 6 mg Subcutaneous
(n = 547) %
Placebo
(n = 370) %
Atypical sensations 42 9
  Tingling 14 3
  Warm/hot sensation 11 4
  Burning sensation 7 < 1
  Feeling of heaviness 7 1
  Pressure sensation 7 2
  Feeling of tightness 5 < 1
  Numbness 5 2
  Feeling strange 2 < 1
  Tight feeling in head 2 < 1
Cardiovascular
  Flushing 7 2
  Chest discomfort 5 1
  Tightness in chest 3 < 1
  Pressure in chest 2 < 1
 Ear, nose, and throat
  Throat discomfort 3 < 1
  Discomfort: nasal cavity/sinuses 2 < 1
Injection site reactiona 59 24
Miscellaneous
  Jaw discomfort 2 0
Musculoskeletal
  Weakness 5 < 1
  Neck pain/stiffness 5 < 1
  Myalgia 2 < 1
Neurological
  Dizziness/vertigo 12 4
  Drowsiness/sedation 3 2
  Headache 2 < 1
Skin
  Sweating 2 1
aIncludes injection site pain, stinging/burning, swelling, erythema, bruising, bleeding.

The incidence of adverse reactions in controlled clinical trials was not affected by gender or age of the patients. There were insufficient data to assess the impact of race on the incidence of adverse reactions.

Cluster Headache

In the controlled clinical trials assessing the efficacy of Imitrex Injection as a treatment for cluster headache (Studies 4 and 5), no new significant adverse reactions were detected that had not already been identified in trials of Imitrex in patients with migraine.

Overall, the frequency of adverse reactions reported in the trials of cluster headache was generally lower than in the migraine trials. Exceptions include reports of paresthesia (5% Imitrex, 0% placebo), nausea and vomiting (4% Imitrex, 0% placebo), and bronchospasm (1% Imitrex, 0% placebo).

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of Imitrex Tablets, Imitrex Nasal Spray, and Imitrex Injection. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Cardiovascular

Hypotension, palpitations.

Neurological

Dystonia, tremor.

What drugs interact with Imitrex (sumatriptan)?

Ergot-containing Drugs

Ergot-containing drugs have been reported to cause prolonged vasospastic reactions. Because these effects may be additive, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and Imitrex Injection within 24 hours of each other is contraindicated.

Monoamine Oxidase-A Inhibitors

MAO-A inhibitors increase systemic exposure by 2-fold. Therefore, the use of Imitrex Injection in patients receiving MAO-A inhibitors is contraindicated.

Other 5-HT1 Agonists

Because their vasospastic effects may be additive, co-administration of Imitrex Injection and other 5-HT1 agonists (e.g., triptans) within 24 hours of each other is contraindicated.

Selective Serotonin Reuptake Inhibitors/Serotonin Norepinephrine Reuptake Inhibitors And Serotonin Syndrome

Cases of serotonin syndrome have been reported during co-administration of triptans and SSRIs, SNRIs, TCAs, and MAO inhibitors.

Summary

Imitrex (sumatriptan) is a selective serotonin receptor agonist (a “triptan”) used to treat migraine headaches. Common side effects of Imitrex include pain or tightness in the chest or throat, tingling, flushing, weakness, dizziness, abdominal discomfort, sweating, nasal irritation, injection site reactions, and allergic reactions (rare). Safe use of Imitrex in pregnancy has not been established. Imitrex is excreted in breast milk. Infant exposure may be reduced by avoiding breastfeeding for 12 hours after administration of Imitrex.

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Medically Reviewed on 5/11/2020
References
FDA Prescribing Information

Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.
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