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Side Effects of Imitrex (sumatriptan)
Imitrex (sumatriptan) is a selective serotonin receptor agonist used to treat migraine headaches. Migraine headaches result from dilatation of blood vessels in the brain. Imitrex relieves migraines by stimulating serotonin receptors in the brain, causing the muscles surrounding the blood vessels in the brain to contract and narrow the blood vessels. It also reduces pain signals transmitted by nerves to the brain. Imitrex does not prevent or reduce 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
- allergic reactions (rare)
Serious side effects of Imitrex are rare and include:
- coronary artery spasm
- heart attacks
- stroke
- abnormal heart beats
- seizures
Drug interactions of Imitrex include monoamine oxidase inhibitors (MAOIs), which may increase blood levels and side effects of Imitrex. Combining Imitrex with sibutramine, selective serotonin reuptake inhibitors (SSRIs), or serotonin and norepinephrine reuptake inhibitors (SNRIs) may cause increased serotonin-related side effects. Administering Imitrex within 24 hours of treatment with an ergot-containing medication is contraindicated because it increases 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 of sumatriptan include:
- pain or tightness in the chest or throat
- tingling
- flushing
- weakness
- dizziness
- abdominal discomfort
- sweating
- nasal irritation
- injection site reactions
Rarely, allergic reactions have been reported, usually in individuals 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:
- coronary artery spasm
- heart attacks
- stroke
- abnormal heart beats
- seizures
Imitrex (sumatriptan) side effects list for healthcare professionals
The following serious adverse reactions are described below and elsewhere in the labeling:
- Myocardial ischemia, myocardial infarction, and Prinzmetal’s angina
- Arrhythmias
- Chest, throat, neck, and/or jaw pain/tightness/pressure
- Cerebrovascular events
- Other vasospasm reactions
- Medication overuse headache
- Serotonin syndrome
- Increase in blood pressure
- Hypersensitivity reactions
- Seizures
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 placebo-controlled clinical trials in migraine patients 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
| 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 reaction | 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 |
| a Includes 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, 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, nausea and vomiting, and bronchospasm.
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.
