If you have migraine, your doctor might suggest Relpax (eletriptan) as a treatment option for you. It’s a prescription medication used to treat migraine symptoms in adults.

Relpax comes as a tablet that you swallow. It’s only used to treat migraine symptoms, not for migraine prevention.

For more information about Relpax, including details about its uses, see this in-depth article on the drug.

Like other drugs, Relpax can cause mild or serious side effects. Keep reading to learn more.

Some people may experience mild or serious side effects of Relpax. Below are some of the most commonly reported side effects from people taking Relpax in studies:

Mild side effects of Relpax may include:

  • dizziness
  • nausea
  • pain, pressure, or tightness in your chest, throat, neck, or jaw
  • sleepiness
  • weakness

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And don’t stop taking Relpax unless your doctor recommends it.

Relpax may cause mild side effects other than the ones listed above. See the Relpax prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Relpax, visit MedWatch.

Serious side effects can happen from taking Relpax. These were rare in studies. When serious side effects did occur, they were more common in people who had certain health conditions besides migraine.

Serious side effects of Relpax that have been reported include:

  • bleeding in the brain and stroke (lack of blood flow to the brain)
  • circulation (blood flow) problems in the hands and feet
  • high blood pressure
  • medication overuse headaches (headaches that can occur if you take Relpax too often)
  • stomach and intestine problems
  • allergic reaction*
  • heart-related side effects*
  • Raynaud’s syndrome (lack of blood flow to the hands and feet)*
  • serotonin syndrome (high levels of a chemical called serotonin in your body)*

If you develop serious side effects while taking Relpax, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.

Get answers to some frequently asked questions about Relpax’s side effects.

Can Relpax cause weight gain?

No, weight gain wasn’t a side effect reported by people taking Relpax in studies.

Some other medications used for migraine treatment can cause weight gain, such as valproic acid. But this hasn’t been reported with Relpax.

If you notice any changes in your weight or if you have concerns about your weight, talk with your doctor or pharmacist.

Does the 40-mg dose have a higher risk of side effects than the 20-mg dose?

Possibly. In studies, the difference in the risk of side effects from the 40-milligram (mg) dose, compared with the 20-mg dose, was very small.

In general, your risk of side effects increases with an increased dose of Relpax. For most people, this increase is small.

Having certain health conditions or taking certain medications may further increase your risk of side effects. For more information, see “Warnings for Relpax” below. You can also talk with your doctor or pharmacist to learn more.

How long do Relpax side effects last? Are any side effects long term?

It depends. Side effects of Relpax are typically mild and go away after a few hours or days. For example, dizziness typically goes away a few hours after taking a dose.

Some rare but serious side effects of Relpax may be long term, such as heart-related problems. For example, there are reports of people having a heart attack as a side effect of Relpax. A heart attack can lead to long-term problems.

Keep in mind that Relpax is only taken as needed when you’re having migraine symptoms. You shouldn’t take it every day or take it to prevent migraine symptoms.

If you have side effects of Relpax that don’t go away, talk with your doctor. They may recommend a different migraine treatment. Your doctor can also provide more information about what to expect with Relpax’s side effects.

Learn more about some of the side effects that Relpax may cause.

Heart-related side effects

Heart-related side effects can occur with Relpax, though they are rare. They may include:

These heart-related side effects have occurred as soon as a few hours after the first dose of Relpax. And these reactions have happened in people without any existing heart problems. In extreme cases, heart-related side effects of Relpax can be fatal.

Your risk of heart-related side effects is higher if you have existing heart problems. It’s also higher if you’re at risk of cardiovascular (heart and blood vessel) disease, including if you:

Before you start taking Relpax, your doctor will evaluate your risk of cardiovascular disease and heart-related side effects. Doctors typically will not prescribe Relpax if you have certain conditions (see “Warnings for Relpax” below for details).

* Sex and gender exist on spectrums. Use of the terms “male” and “female” in this article refers to sex assigned at birth.

What might help

Depending on your risk factors for cardiovascular disease, your doctor may have you take your first Relpax dose in their office or clinic. They’ll then monitor your heart using an electrocardiogram. This is a test that monitors your heart rhythm and electrical activity.

If your doctor prescribes Relpax, they’ll likely continue to check your heart health while you’re taking the drug.

If you have symptoms of a heart attack, stop taking Relpax and get medical help right away. These symptoms can include:

  • chest discomfort or pain
  • cold sweats
  • discomfort or pain in your arms, back, jaw, neck, or stomach
  • feeling lightheaded
  • nausea or vomiting
  • shortness of breath

Serotonin syndrome

While it’s not common, taking Relpax can cause serotonin syndrome as a side effect.

Serotonin syndrome refers to high levels of serotonin in your blood. Serotonin is a chemical that your body makes. It helps your brain cells and nerves function and has other important roles. Serotonin syndrome can be life threatening, in extreme cases.

Symptoms of this condition can include:

Serotonin syndrome is most likely when you first start taking Relpax, or if your doctor increases your dosage. Symptoms can even occur within minutes of taking the first dose or higher dose.

Taking other medications that can raise your serotonin levels can increase your risk of serotonin syndrome from taking Relpax. Examples of these medications include selective serotonin reuptake inhibitors and tricyclic antidepressants.

What might help

If you notice symptoms of serotonin syndrome while taking Relpax, contact your doctor right away. If your symptoms feel life threatening, seek emergency medical help.

Your doctor will likely have you stop taking Relpax if you experience serotonin syndrome.

Raynaud’s syndrome

Treatment with Relpax can cause Raynaud’s syndrome (also called Raynaud’s phenomenon or disease). This is rare.

With this condition, you have narrowed blood vessels that supply blood to your feet and hands. This can cause:

  • numbness in your fingers or toes, which may occur with pain or tingling
  • fingers or toes that appear blue or white, then red as blood flow returns
  • cramping, numbness, pain, or weakness in your legs

Cold temperatures or stress can trigger symptoms of Raynaud’s syndrome.

What might help

If you notice symptoms of Raynaud’s syndrome while taking Relpax, contact your doctor. They’ll likely want to examine your symptoms. They may recommend stopping Relpax and taking a different migraine treatment.

Allergic reaction

Like most drugs, Relpax can cause an allergic reaction in some people.

Symptoms can be mild or serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine), or a topical product, such as hydrocortisone cream, to manage your symptoms.

If your doctor confirms that you had a mild allergic reaction to Relpax, they’ll decide if you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms that you had a serious allergic reaction to Relpax, they may have you switch to a different treatment.

Keeping track of side effects

During your Relpax treatment, consider keeping notes about any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dosage of the drug you were taking when you had the side effect
  • how soon after starting that dosage you experienced it
  • the specific symptoms of the side effect
  • how it affected your daily activities
  • any other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Relpax affects you. And your doctor can use this information to adjust your treatment plan if needed.

Relpax may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Relpax. The list below includes factors to consider.

Circulation (blood flow) problems, including ischemic bowel disease and peripheral vascular disease. Doctors typically will not prescribe Relpax if you have circulation problems because Relpax can cause or worsen these problems. Talk with your doctor about other migraine treatments instead.

Heart problems, including high blood pressure that isn’t managed. Your doctor typically will not prescribe Relpax if you have a heart problem, such as:

Relpax can cause heart problems as a side effect, and these problems can be fatal, in extreme cases. If you already have heart problems, taking Relpax may worsen your condition. Talk with your doctor about other migraine treatments.

Stroke. Doctors typically will not prescribe Relpax if you’ve had a stroke. Relpax can cause a stroke as a side effect, in extreme cases. If you’ve had a stroke in the past, you have a higher risk of this side effect. Talk with your doctor about other migraine treatments.

High cholesterol. Talk with your doctor before you start taking Relpax if you have high cholesterol. Having high cholesterol raises your risk of heart problems, such as a heart attack, which are possible side effects of Relpax. Your doctor can decide whether taking Relpax is safe for you.

Smoking or other tobacco use. Talk with your doctor if you smoke or otherwise use tobacco. This raises your risk of heart problems, which are possible side effects of Relpax treatment. Your doctor can decide whether it’s safe for you to take Relpax.

Severe liver problems. Your body uses your liver to break down and help get rid of Relpax. Having severe liver problems may make it harder for your body to break down Relpax. This can raise levels of the drug in your body, which may raise your risk of side effects. People with mild or moderate liver problems can usually take Relpax without issues. Your doctor can determine whether Relpax is safe to take, based on your condition.

Allergic reaction. If you’ve had an allergic reaction to Relpax or any of its ingredients, your doctor will likely not prescribe this drug. Ask them what other medications are better options for you.

Alcohol use and Relpax

There’s no known interaction between alcohol and Relpax.

But in some people, drinking alcohol can trigger migraine symptoms. Talk with your doctor if you drink alcohol and are concerned about how it may affect your migraine symptoms. They can tell you how much alcohol is safe for you to drink.

Pregnancy and breastfeeding while taking Relpax

It’s not known whether it’s safe to take Relpax while pregnant. If you’re pregnant or planning to become pregnant, talk with your doctor before taking Relpax. They may recommend a different medication to treat your migraine symptoms.

Relpax is known to pass into breast milk if a person takes it while breastfeeding. But it’s not known whether this causes side effects in a breastfed child. Your doctor may recommend avoiding breastfeeding for 24 hours after taking a Relpax dose. They may also recommend other feeding options for your child.

Relpax is a prescription medication used to treat migraine symptoms when they happen. If you’re interested in treatment with Relpax, talk with your doctor or pharmacist.

Be sure to ask any questions that will help you decide how comfortable you are taking Relpax. Some examples to get you started include:

  • Should I still take my other migraine medications while I’m taking Relpax?
  • Can I take any treatments with Relpax for migraine prevention?
  • Are there treatments for any side effects of Relpax?

For first-hand stories from others living with your condition and advice about managing it, sign up for Healthline’s migraine newsletter.


Do any medications raise my risk of side effects if I take them with Relpax?



Yes. Drugs called CYP3A4 inhibitors can increase the risk of side effects if they’re taken with Relpax.

Examples of these drugs, which should not be taken with Relpax, include ketoconazole, itraconazole, clarithromycin, and ritonavir.

Relpax should also not be taken with other migraine treatments, such as medications containing ergotamine.

You should talk with your doctor about all of the medications you take before starting Relpax. And if any medications are prescribed to you while you’re taking Relpax, be sure your doctor and pharmacist know you’re also taking Relpax.

Dena Westphalen, PharmDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.