If you have a certain kind of headache, you may be interested in learning more about sumatriptan. It’s a generic prescription drug used to treat the following conditions in adults:

Sumatriptan (also called sumatriptan succinate) comes as a tablet you swallow. It also comes in nasal spray and injectable forms, but those are not covered in this article. Sumatriptan is also available as the brand-name drug Imitrex, which comes as a tablet and in other forms.

Sumatriptan can be used short or long term depending on the condition it’s being used to treat.

Sumatriptan’s side effects are usually mild. Serious side effects are rare and often related to the drug’s effect on a chemical in the brain called serotonin. This article describes sumatriptan’s side effects, also referred to as adverse effects.

For more information about sumatriptan, including details about its uses, see this in-depth article.

* For this condition, only the injectable form of sumatriptan is used.

Some people may experience mild to serious side effects during their sumatriptan treatment. Examples of the drug’s commonly reported side effects include:

  • fatigue (low energy)
  • feeling generally unwell
  • pain, pressure, or tightness in your chest, neck, throat, or jaw
  • feeling warm or cold
  • vertigo (a feeling of spinning)
  • numbness or tingling*

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

Sumatriptan may cause mild side effects. These usually go away on their own. Examples of mild side effects that have been reported with sumatriptan include:

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

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

Sumatriptan may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

Serious side effects have been reported with sumatriptan. These include:

If you develop serious side effects while taking sumatriptan, call your doctor right away. If the side effects seem life threatening or 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.

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 sumatriptan, visit MedWatch.

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

Does the risk of side effects vary with higher doses of sumatriptan (25 mg, 50 mg, 100 mg)?

Yes, studies of sumatriptan showed that higher doses sometimes caused more side effects. The 25-milligram (mg) dose was considered the lower dose in these studies. Your doctor will likely prescribe the lowest dose of sumatriptan that meets your needs.

Your risk of side effects depends on several factors in addition to dosage. These include:

  • the severity of the condition you’re using sumatriptan to treat
  • how often you take sumatriptan
  • other health conditions you have

Talk with your doctor about how to decrease your risk of side effects from sumatriptan.

Can sumatriptan cause long-term side effects? If so, how long might they last?

Possibly. Long-term side effects usually start while you’re taking sumatriptan and continue for a long time. Some of the side effects reported in the drug’s studies that could possibly become long-term health problems include:

Talk with your doctor about ways to reduce your risk of long-term side effects from sumatriptan.

Are the side effects of sumatriptan tablet different from those of the nasal spray and injection forms?

Sometimes. Certain rare side effects seen in sumatriptan studies are similar with all forms of the drug. These include high blood pressure and serotonin syndrome (a high level of the chemical serotonin). This is because these are side effects that happen after your body absorbs the drug.

Other side effects are specific to the drug’s form. For example, the nasal spray is more likely to cause nose discomfort. And the injectable forms can cause injection site reactions, such as pain or redness.

Talk with your doctor about the form of sumatriptan that will work best for you. For instance, if you take sumatriptan for migraine headaches and you are too nauseous to swallow a pill, one of the other forms may be a better choice.

Is rebound headache a side effect of sumatriptan?

Yes, it can be. Rebound headache is also called medication overuse headache. It was a rare side effect in studies of sumatriptan. It’s more likely when you take the drug for more than 10 days each month.

This is a serious side effect because it means your migraine episodes may be harder to treat later. Talk with your doctor about migraine prevention treatments that will help you use sumatriptan less often.

Does sumatriptan cause weight gain?

No, weight gain was not a side effect reported in sumatriptan studies. But other sumatriptan side effects might lead to weight gain. For example:

  • If you feel chest or throat tightness, you may be less likely to exercise.
  • If you have vertigo (a feeling of spinning), you may be cautious about exercise that requires balance.
  • If you have nausea, you may change your usual diet.

Talk with your doctor about sumatriptan side effects that interfere with your diet or exercise routine. They may have suggestions to help you get back on track.

Learn more about some of the side effects sumatriptan may cause. Certain side effects can either be mild or a sign of something more serious. Talk with your doctor about how to tell the difference.

Drowsiness

Drowsiness was a rare side effect in studies of sumatriptan. Fatigue (low energy) was a common side effect. People sometimes use those two words to mean the same thing.

Drowsiness is when you feel less alert than usual during the day. If you have this side effect, avoid tasks that require alertness and coordination such as driving.

Migraine headaches can also cause drowsiness. So it’s possible you could be having a symptom of your condition, not a side effect of the drug.

What might help

There are several lifestyle changes that can decrease your overall risk of drowsiness. These include:

  • getting enough sleep
  • stress management
  • frequent breaks during work
  • exercise

If you notice drowsiness when you take sumatriptan, make a note of how long it lasts. (This can be part of keeping an overall side effects journal.) This will help you plan around the drowsiness.

Talk with your doctor if drowsiness from sumatriptan is interfering with your usual activities. They may have suggestions that help, including prescription medications to help keep you alert. They may also recommend a different migraine treatment option.

Stomach (belly) pain

Stomach pain was a rare side effect in studies of sumatriptan. But severe or sudden belly pain is one of the warning signs of low blood flow to the digestive system. And this is a serious possible side effect of the drug. Other symptoms to watch out for include:

  • pain after eating
  • weight loss
  • bloody diarrhea
  • fever

If you have sudden, severe stomach pain, this may be a sign of a medical emergency.

What might help

Call your doctor or 911, or go to your nearest emergency department if you think you may be having a medical emergency. This is especially true if you have belly pain that happens along with other symptoms to watch out for.

If your belly pain is mild but lasts for more than a week or so, talk with your doctor. This could be a mild, temporary side effect. It could also arise from an unrelated cause, such as changes in your diet.

Talk with your doctor about how to tell the difference between mild and serious sumatriptan side effects.

Nausea

Nausea was a rare side effect in studies of sumatriptan. Similar to the side effect of belly pain just above, nausea can be either mild and temporary, or a sign of a more serious problem.

Severe or sudden nausea may be a symptom of these serious sumatriptan side effects:

Nausea is also a common symptom of migraine. So mild nausea could be a symptom of your condition rather than a side effect of the drug.

What might help

If you think you are experiencing a medical emergency, call your doctor right away or go to your nearest emergency department.

If the nausea is mild, there are several treatment options, which include:

  • using over-the-counter (OTC) medications such as Dramamine or Tums
  • eating a bland diet
  • avoiding nausea triggers like strong smells or humid places

Talk with your doctor if the nausea does not go away in a few days. They may have additional OTC or prescription treatment suggestions.

Dizziness

Dizziness was a rare side effect in sumatriptan studies. But vertigo (a feeling of spinning) was a more common side effect. People sometimes use those words to mean the same thing.

Symptoms of dizziness include:

Like other side effects in this section, dizziness may also be a sign of a more serious side effect. If the dizziness is sudden or severe, it may be a sign of:

Dizziness can be caused by several different things. Because it’s also a symptom of headache, you may be having a symptom not a drug side effect.

What might help

If you think you’re having a medical emergency, call your doctor right away or go to your local emergency department.

If the dizziness is mild, there are several possible treatment options, which include:

  • drinking plenty of fluids
  • identifying and avoiding headache triggers (if dizziness is a headache symptom)
  • avoiding alcohol
  • monitoring your blood pressure
  • using stress management techniques

If the dizziness happens frequently or does not go away quickly, talk with your doctor. They can help you identify the cause. If it’s a sumatriptan side effect, your doctor may adjust your dose or choose a different medication for you.

Numbness or tingling in the arms, legs, hands, and feet

A mild, common side effect in sumatriptan studies was numbness or tingling.* Some people may experience this as a burning sensation. Another common sumatriptan side effect is a feeling of warmth, which could also feel like a burning sensation.

These sensations can happen anywhere in the body but are common in the hands, feet, face, legs, and arms.

* This sensation can also be caused by pressure on the blood vessels from sitting or standing in one position for a while.

What might help

This side effect usually goes away on its own. If it doesn’t go away after a few days, talk with your doctor. They can determine if it’s from sumatriptan or an unrelated cause and will change your dose of the drug accordingly.

If the numbness and tingling is severe or sudden, it could be a sign of a more serious sumatriptan side effect, such as stroke. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Allergic reaction

Like most drugs, sumatriptan can cause an allergic reaction in some people. Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, usually 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 a treatment to manage your symptoms. Examples include:

  • an antihistamine you swallow, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to sumatriptan, 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 you’ve had a serious allergic reaction to sumatriptan, they may have you switch to a different treatment.

Keeping track of side effects

During your sumatriptan treatment, consider taking notes on any side effects you’re having. You can then 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 dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

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

Sumatriptan may not be right for you if you have certain medical conditions. (This is known as a drug-condition interaction.) Other factors may also affect whether sumatriptan is a good treatment option for you.

Talk with your doctor about your health history before starting sumatriptan. Factors to consider include those described below. Some of them may prevent your doctor from prescribing sumatriptan due to the risk of harm.

Seizures. Seizures are a possible side effect of sumatriptan. If you already have seizures, sumatriptan could make them more frequent. This could also happen if you take other medications that increase your likelihood of having seizures.

Low blood flow to the limbs or digestive system. Another possible side effect of sumatriptan is decreased blood flow to the limbs or the digestive system. If you already have problems with blood flow (ischemia), then your doctor will likely not prescribe sumatriptan for you.

High blood pressure. If your high blood pressure is not well managed, your doctor will likely not prescribe sumatriptan for you. If you have high blood pressure that’s managed with medication, your doctor may prescribe sumatriptan, but they’ll frequently monitor your blood pressure.

Liver problems. If you have decreased liver function, your doctor may prescribe a lower dose of sumatriptan for you. If your liver problems are severe, they’ll likely suggest a different treatment for your condition.

Drugs that affect serotonin. Serotonin syndrome (a high level of the chemical serotonin) is a possible side effect of sumatriptan. If you already take drugs that increase your risk of this side effect, sumatriptan can make your risk even higher. Symptoms of serotonin syndrome include:

  • fast heartbeat
  • changes in mental state, such as having hallucinations (seeing or hearing things that aren’t really there)
  • vomiting
  • trouble with coordination

Examples of medications that can increase your risk of serotonin syndrome include: fluoxetine, venlafaxine, amitriptyline, and phenelzine.

Sumatriptan should also not be taken with drugs in a group called monoamine oxidase inhibitors (MAOIs). Your doctor will likely recommend that you wait at least 2 weeks between taking sumatriptan and an MAOI.

And sumatriptan should not be taken within 24 hours of any drug that contains ergotamine. (These drugs are sometimes prescribed for headache.)

Previous stroke. If you’ve had a stroke or transient ischemic attack (ministroke), your doctor will likely not prescribe sumatriptan for you. This is because the drug has a side effect of increased risk of brain injury events, including stroke and hemorrhage. And if you’ve already had a stroke, your risk is too high.

Heart problems. Your doctor will likely order tests to check your heart function before you start sumatriptan. These tests may be more involved if you have a history of heart problems. If you have certain heart problems, your doctor will likely not prescribe sumatriptan for you. These include:

Sumatriptan also has a side effect that mimics heart attack symptoms. If you have heaviness, pressure, pain, or tightness in your chest, neck, throat, or jaw, call your doctor right away. They’ll check to see if your symptoms are heart related.

Heart rhythm problems. If you have certain heart rhythm problems, such as Wolff-Parkinson-White Syndrome, your doctor will likely not prescribe sumatriptan for you. This is because the drug can cause changes in heart rhythm that may lead to serious health problems or even death. Talk with your doctor if you have a history of arrhythmias.

Allergic reaction. If you’ve had an allergic reaction to sumatriptan or any of its ingredients, your doctor will likely not prescribe it for you. Ask them about other medications that might better treatment options.

Alcohol and sumatriptan

Alcohol does not directly interact with sumatriptan. But drinking alcohol while taking this drug may increase your risk of side effects they can both cause. For example, both alcohol and sumatriptan have possible side effects of drowsiness, vertigo (a feeling of spinning), and increased risk of heart and blood vessel conditions. These side effects and risks could be worse if you drink alcohol while taking sumatriptan.

If you drink alcohol, talk with your doctor about how much, if any, is safe to use with this medication.

Pregnancy and breastfeeding while taking sumatriptan

There’s not enough information about taking sumatriptan while pregnant or breastfeeding to determine if it’s safe to take during these times. Studies have shown that sumatriptan passes into breastmilk, but its effects on a breastfed child aren’t currently known. Talk with your doctor about risks and benefits of taking sumatriptan if you’re pregnant, breastfeeding, or plan to be either.

If you have questions about side effects that sumatriptan can cause, talk with your doctor. You can also ask them about Imitrex, which is the brand-name version of sumatriptan. A generic drug and its brand-name version are expected to have the same side effects because they contain the same active ingredient. (An active ingredient is what makes a drug work.)

Here are a few ideas for questions you may want to ask your doctor.

  • Does my risk of high blood pressure increase if I take a higher dose of sumatriptan?
  • Are side effects from sumatriptan worse than those from other drugs that treat migraine?
  • Will my rebound headaches go away if I switch to a drug other than sumatriptan?
  • Can sumatriptan cause liver problems?
  • How can I tell if sumatriptan side effects are signs of a more serious problem?

To learn more about sumatriptan or Imitrex oral tablets, see these articles:

To get information on different conditions and tips for improving your health, subscribe to any of Healthline’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

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.