Imitrex is a brand-name drug used to treat migraine headaches with or without aura. The generic drug is sumatriptan.
Imitrex belongs to a class of drugs known as selective serotonin receptor agonists (triptans). It causes blood vessels in the head to narrow, which stops pain signals from being sent to the brain. It also blocks the release of certain substances that cause migraine symptoms, including pain, nausea, and hypersensitivity to light and sound.¹
The US Food and Drug Administration (FDA) warns of serious adverse effects with Imitrex use. This include:²
Myocardial ischemia/infarction and Prinzmetal’s angina — you will undergo cardiac evaluation if you are at risk of cardiovascular events
Arrhythmias (abnormal heart rhythm) — Imitrex must be discontinued if arrhythmias occur
Pain, tightness, or pressure in the chest, throat, neck, and/or jaw. These symptoms could indicate a heart problem. Your doctor will evaluate you for coronary artery disease if you are at risk.
Cerebral hemorrhage, subarachnoid hemorrhage, and stroke — Imitrex must be discontinued if these adverse effects occur
Peripheral vasospastic reactions or gastrointestinal ischemic reaction — Imitrex must be discontinued if these adverse effects occur
Medication overuse headache — you will need to undergo detoxification guided by your doctor
Serotonin syndrome — Imitrex must be discontinued if this occurs
Seizures — Imitrex should be used with caution if you have epilepsy or a lowered seizure threshold
Imitrex is contraindicated in the following conditions:
Past diagnosis of coronary artery disease (including any history of myocardial infarction, angina, or silent ischemia), or history of coronary artery vasospasm
Wolff-Parkinson-White syndrome (a serious skin condition) or other disorders of the cardiac accessory conduction pathway
Past diagnosis of stroke, hemiplegic or basilar migraine, or transient ischemic attack
Ischemic bowel disease
Hypersensitivity to Imitrex (some people have experienced allergic reactions like angioedema and anaphylaxis)
Severe liver impairment
Do not take Imitrex if:
You have taken another 5-HT1 agonist (such as another triptan) or a medication containing ergotamine in the last 24 hours.
You are currently taking a monoamine oxidase-A inhibitor (MAOI) or have taken one in the last two weeks.
Imitrex is used to treat migraine headaches. It helps relieve severe pain and other symptoms, like nausea, vomiting, and sensitivity to light and sound.
Imitrex won’t prevent migraine headaches or reduce the number of migraine headaches you get.
The Imitrex injection is also indicated to treat cluster headaches.
The drug comes in different strengths and formats, including:
Tablets for oral use: 25mg, 50mg, or 100mg
Nasal spray: 5mg or 20mg
Injection (pre-filled single-dose cartridges for use with Imitrex Statdose auto-injector pen): 4mg or 6mg
Imitrex works best if taken at the first sign of a migraine attack when your headache is still mild.
Do not take more Imitrex than what is prescribed by your doctor. Your dosage will depend on the severity of your condition, the form of Imitrex you take, and other medical conditions you may have.
Swallow the tablet whole with a glass of water. You can take it with or without food.
If you don’t feel any better after two hours of taking your dose, or you only feel relief for a short time, you can take a second dose. Do not take a second dose within two hours of your first dose.
You must not take more than 200mg in 24 hours.²
To take a 5mg or 20mg dose, spray once in one nostril. To take 10mg, spray 5mg in each nostril.
If you don’t feel any better after two hours of taking your dose, or you only feel relief for a short time, you can take one additional dose. Do not take a second dose within two hours of your first dose.
You must not take more than 40mg in 24 hours.³
Imitrex injections are usually administered in the emergency department for severe acute migraine or cluster headache attacks.
6mg will be administered under the skin. Your doctor may recommend taking the lower dose of 4mg to treat migraine headaches, but the efficacy of this dose for cluster headaches is unknown.
You should not take more than 12mg cumulatively over 24 hours. Two 6mg injections must be taken at least one hour apart.
Only consider taking a second 6mg dose if you notice some response to the first. This is because Imitrex in this form could quickly cause severe adverse effects, particularly if your diagnosis is incorrect and your headache is a symptom of a different condition where Imitrex is contraindicated.⁴
Imitrex tablets work within 30–60 minutes; the injection provides relief in 10–15 minutes; the nasal spray works within 15 minutes.⁵
This drug is not suitable for people who:
Want to take medication to prevent migraine headaches — this drug only helps ease the symptoms
Have hemiplegic or basilar migraines
Have uncontrolled high blood pressure
Have heart problems or a history of heart problems
Have a history of stroke, blood circulation problems, or transient ischemic attacks
Have peripheral vascular disease (narrowing of blood vessels in your legs, arms, stomach, or kidneys)
Have taken one of these medications in the last 24 hours: frovatriptan (Frova), eletriptan (Relpax), almotriptan (Axert), rizatriptan (Maxalt or Maxalt MLT), naratriptan (Amerge), sumatriptan and naproxen (Treximet), ergotamines (Cafergot, Ergomar, or Migergot) or dihydroergotamine (DHE-45 injection, Trudhesa nasal spray, or Migranal nasal spray)
Are younger than 18 years of age
Like all medicines, Imitrex can cause side effects. Most common side effects disappear as your body adjusts to the drug.
Imitrex tablets can cause the following common side effects:²
A sensation of pain, tightness, pressure, or heaviness in the chest and/or throat
Feeling cold or warm
A tingling sensation
Imitrex nasal spray can cause the following common side effects:³
A burning sensation
Irritation in your nose or throat
Nausea and/or vomiting
An unpleasant or unusual taste
The Imitrex injection can cause the following common side effects:⁴
A tingling sensation
A burning sensation
Feeling warm or hot
Feeling tightness, heaviness, or pressure
Tightness in the head
Feeling tightness, pressure, or discomfort in the chest
Irritation in your nose or throat
Irritation at the injection site (pain, redness, and swelling)
Stiffness or pain in the neck
Myalgia (muscle pain or aches)
This list is not exhaustive, and other side effects may occur. Talk to your doctor if these symptoms persist, worsen, or bother you.
Imitrex can cause severe side effects. Call your doctor immediately or seek medical assistance if you experience any of the following serious side effects:
Heart problems, including myocardial ischemia, myocardial infarction (heart attack), and Prinzmetal’s angina. You may experience chest discomfort, pain or discomfort in your arms, back, neck, jaw, or stomach, shortness of breath, cold sweats, nausea, or lightheadedness.⁶
Arrhythmias (irregular heartbeat). You may experience heart palpitations, anxiety, confusion, pain or discomfort in your chest, trouble breathing, gasping during sleep, dizziness, fainting, or feeling weak or tired.⁷
Cerebrovascular events, including bleeding in the brain and stroke. Immediately call 911 if you experience severe headache, numbness or weakness in your face, arm, or leg (this may affect one side of the body), sudden confusion, trouble understanding speech or speaking, sudden difficulty walking, loss of balance, dizziness, poor coordination, or sudden sight difficulties in one or both eyes.⁸
Other vasospasms (a narrowing of the arteries, which leads to reduced blood flow) that are not related to the heart. Types of vasospasm may include Raynaud’s syndrome. Look out for a change of color in your fingers or toes, along with feeling cold, numbness, pain, pins and needles, or trouble moving the area. Imitrex may also cause reduced blood flow to the gastrointestinal system, which can present as bloody diarrhea and stomach pain.⁹
Medication overuse headache. Overusing Imitrex or using it for a longer period of time may have the opposite effect of treating your migraines, causing an increase in the frequency and/or severity of your headaches. Speak to your doctor if you notice this exacerbation. Detoxification (where Imitrex is discontinued safely and other alternatives are introduced to manage your current symptoms) must be performed under medical guidance.
Serotonin syndrome: This could occur as an adverse reaction to using the injection form, particularly if you use other mental health medications, such as selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), or MAO inhibitors. Symptoms include fast heart rate, shivering, tremor, sweating, dilated pupils, uncontrolled eye movements, involuntary twitching or jerking, high body temperature, gas, diarrhea, increased alertness, agitation, muscle rigidity, seizure, and delirium. Serotonin syndrome can result in coma or death.¹⁰
Significant increase in blood pressure and hypertensive crisis in some cases. Symptoms may include headache, dizziness, a change in mental function, shortness of breath, chest pain, reduced urination, vomiting, and vision changes.¹¹
Anaphylactic reactions. Symptoms include a skin rash with or without itchy, swollen, red, blistered, or peeling skin, wheezing, difficulty speaking or breathing, swollen mouth, face, lips, tongue, or throat, and tightness in your chest or throat.
Seizures. At the start of a seizure, you may see strange lights or hear sounds. Other symptoms include making a loud noise or a cry, muscle stiffness, twitching, convulsions, difficulty breathing, gasping for air, and fainting.
Do not take more Imitrex than what your doctor recommends. Do not take two doses closer in time to each other than instructed. Doing so could lead to an overdose and potentially fatal side effects.
Symptoms of overdose may include the following:
Difficulty breathing and reduced breathing rate
Redness on the skin of the arms or legs
Bluish face and lips
Loss of consciousness
If you suspect that you or someone you know has overdosed on Imitrex, seek immediate emergency medical assistance by calling 911.
Allergic reactions are a potential serious side effect of Imitrex.
Stop taking Imitrex and seek emergency medical help if you develop the following symptoms:
Skin rash with or without itchy, swollen, red, blistered, or peeling skin
Difficulty speaking or breathing
Swollen mouth, face, lips, tongue, or throat
Tightness in your chest or throat
If you are taking the Imitrex injection, note that some needle protectors contain latex. Tell your doctor if you are allergic to latex before taking this medication.
Imitrex is not meant for daily or long-term use. You should only take it to treat migraine headaches, not prevent them.
It is unknown whether Imitrex is safe to treat more than four headaches per month. If you have more than four headaches per month, inform your doctor before taking more of this medication.²
Taking this medication more frequently and for a long time period (for ten days or more per month), or in combination with other migraine medications, can cause medication overuse headaches. This is where the severity or frequency of your headaches worsens.
Treatment for medication overuse headache will involve following your doctor’s guidance on detoxification closely and using other medications to treat your withdrawal symptoms.
Imitrex is a pregnancy category C medication. This means the risk of using this medication during pregnancy cannot be ruled out.
Imitrex and other triptans are thought to be safe for use during pregnancy. Although human data is limited, the available studies have not shown an increased risk of adverse effects on the fetus.
However, animal research has shown that Imitrex use could be unsafe.
Imitrex is considered safer than other migraine drugs, such as dihydroergotamine and ergotamine tartrate, which are contraindicated to use during pregnancy.¹²
This drug can pass into breast milk in low concentrations.
Ask for your doctor’s advice around taking Imitrex while breastfeeding.
Imitrex is not meant for daily use, so you do not need to worry about missing a dose.
Take this medication as directed by your doctor when you have a migraine headache.
This drug does not prevent headaches, so do not take this drug if you don’t have one. Doing so could result in adverse reactions or medication overuse headaches.
Imitrex is known to interact with some drugs to cause a high level of serotonin in your body. This rare but serious condition is known as serotonin syndrome. Some of the medications that Imitrex interacts with include:²
Monoamine oxidase inhibitors (MAOIs), like tranylcypromine (Parnate), phenelzine (Nardil), isocarboxazid (Marplan), and selegiline (Emsam)
Other triptans, like frovatriptan (Frova), eletriptan (Relpax), almotriptan (Axert), rizatriptan (Maxalt or Maxalt MLT), naratriptan (Amerge), and sumatriptan with naproxen (Treximet). Do not take these drugs within 24 hours of taking Imitrex.
Drugs containing ergot, like ergotamine (Ergomar) or caffeine with ergotamine (Cafergot or Migergot). Do not take these drugs within 24 hours of taking Imitrex.
This list is not exhaustive. Tell your doctor about all prescription and non-prescription medicines you currently take.
Drinking alcohol 30 minutes before taking Imitrex is not thought to affect how the drug works. However, you are advised to limit or avoid alcohol consumption if you suffer from migraines, as drinking alcohol can trigger or worsen migraine attacks.²
Before taking Imitrex, discuss the following things with your doctor:
Drug allergies: Tell your doctor if you are allergic to Imitrex or any other drug. Tell them if you have ever had an allergic reaction to Imitrex or another drug.
Medications: Provide your doctor with a list of prescription and non-prescription medications, vitamins, and herbal remedies you are currently taking. Imitrex interacts with several drugs and can cause a serious condition called serotonin syndrome. Tell your doctor if you start taking any new medication while taking Imitrex.
Medical conditions: Inform your doctor of your complete medical history. They must know if you currently have or have had high cholesterol, high blood pressure, diabetes, mental health issues, kidney or liver disease, epilepsy or seizures, heart conditions, circulation problems, or stroke. They must also know your alcohol consumption habits and whether you smoke cigarettes.²
Pregnancy/breastfeeding: Let your doctor know if you are pregnant, planning a pregnancy, or breastfeeding.
Take this medicine only when you have a migraine headache or as directed by your doctor.
If you want to stop taking this drug because of minor side effects, let your doctor know about your concerns. They may suggest taking a different drug to help ease your symptoms. However, if you experience a severe reaction or serious side effect, discontinue taking this drug immediately and contact the emergency services.
1992: The FDA approves Imitrex for use in the US as an injection.
1995: The oral tablet form of Imitrex is approved.
1997: Imitrex nasal spray is approved by the FDA.¹³
The following tips and advice could help you take Imitrex safely and get the best results:
Imitrex can cause drowsiness, dizziness, or weakness. Do not drive or use machinery when taking this medicine until you know how it affects you.
Do not take more of this drug than your doctor recommends. Doing so could lead to harmful effects.
Keep a headache diary by writing down when you have a headache and when you take Imitrex.
Do not share your prescription with other people.
Store Imitrex tablets, nasal spray, or injections at 36–86°F (2–30°C). Keep the medication out of direct light.
To get the best results, take Imitrex at the first sign of a migraine attack when the headache is still mild.
Remember, Imitrex won’t prevent migraine headaches or reduce the number of migraine headaches you get. The medication is used to ease migraine symptoms only.
Imitrex eases migraine symptoms like pain and nausea by causing the blood vessels in the head to narrow. This stops pain signals from being sent to the brain. It also stops certain substances that cause migraine symptoms from being released.
It usually takes 30–60 minutes for Imitrex tablets to work. You may experience relief 10–15 minutes after Imitrex in injection form has been administered. The nasal spray works within 15 minutes.
Sumatriptan | MedlinePlus
Label: Imitrex- sumatriptan spray | DailyMed
Label: Imitrex- sumatriptan injection | DailyMed
Sumatriptan | NHS
Warning signs of a heart attack | Heart Attack and Stroke Symptoms
Symptoms | National Heart, Lung, and Blood Institute
Stroke signs and symptoms | Centers for Disease Control and Prevention
Raynaud's | NHS
Serotonin syndrome (2013)
Hypertensive emergency (2022)
Triptans in pregnancy (2008)
Imitrex | Drugs.com
Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.
However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.
It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.
Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.