Sumatriptan is a headache medicine that narrows blood vessels around the brain. Sumatriptan also reduces substances in the body that can trigger headache pain, nausea, sensitivity to light and sound, and other migraine symptoms.

Sumatriptan is used to treat migraines and cluster headaches in adults. Sumatriptan will only treat a headache. This medicine will not prevent headaches or reduce the number of attacks.

Sumatriptan should not be used to treat a common tension headache, or a headache that causes loss of movement on one side of your body. Use this medicine only if your condition has been confirmed by a doctor as migraine headaches.

Sumatriptan may also be used for purposes not listed in this medication guide.

You should not use sumatriptan if you have ever had heart disease, coronary artery disease, blood circulation problems, Wolff-Parkinson-White syndrome, uncontrolled high blood pressure, severe liver disease, a heart attack or stroke, or if your headache seems to be different from your usual migraine headaches.

Do not use this medicine if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

Do not use sumatriptan within 24 hours before or after using another migraine headache medicine.

Use sumatriptan as soon as you notice headache symptoms. Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Never use more than your recommended dose. Overuse of migraine headache medicine can make headaches worse. Tell your doctor if the medicine seems to stop working as well in treating your migraine attacks.

Sumatriptan is injected under the skin. A healthcare provider may teach you how to properly use the medication by yourself.

This medicine comes in a vial (bottle), a needle-free injector device, or a prefilled cartridge for an auto-injector syringe. Each type is for one use only.

Read and carefully follow any Instructions for Use provided with your medicine. Do not use sumatriptan if you don't understand all instructions for proper use. Ask your doctor or pharmacist if you have questions.

Prepare your injection only when you are ready to give it. Do not use a vial if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

After an injection: If your headache does not completely go away, call your doctor before using a second injection. If your headache goes away and then comes back, use a second injection if it has been at least 1 hour since your first injection. Do not use more than 2 injections in 24 hours. Call your doctor if your symptoms do not improve.

Store at room temperature away from moisture, heat, and light. Throw away any unused medicine after the expiration date on the label has passed.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

You should not use sumatriptan if you are allergic to it, if you have a headache that seems different from your usual migraine headaches, or if you have ever had:

• heart problems, or a stroke (including "mini-stroke");

• coronary artery disease, angina (chest pain), blood circulation problems, lack of blood supply to the heart;

• circulation problems affecting your legs, arms, stomach, intestines, or kidneys;

• a heart disorder called Wolff-Parkinson-White syndrome;

• uncontrolled high blood pressure; or

• severe liver disease.

Do not use sumatriptan if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

Tell your doctor if you have ever had:

• liver or kidney disease;

• epilepsy or other seizure disorder;

• high blood pressure, a heart rhythm disorder; or

• risk factors for coronary artery disease (such as diabetes, menopause, smoking, being overweight, having high blood pressure or high cholesterol, having a family history of coronary artery disease, or being older than 40 and a man).

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Sumatriptan can pass into breast milk. Do not breast-feed within 12 hours after using sumatriptan. If you use a breast pump during this time, throw out any milk you collect. Do not feed it to your baby.

Sumatriptan injection is not approved for use by anyone younger than 18 years old.

Since sumatriptan is used when needed, it does not have a daily dosing schedule. Call your doctor if your symptoms do not improve after using this medicine.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include tremors, skin redness in your arms or legs, weakness, loss of coordination, breathing problems, blue-colored lips or fingernails, vision problems, or a seizure (convulsions).

Do not use sumatriptan within 24 hours before or after using another migraine headache medicine, including:

• sumatriptan tablets or nasal spray, almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, zolmitriptan; or

• ergot medicine such as dihydroergotamine, ergotamine, ergonovine, or methylergonovine.

Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Sumatriptan may cause serious side effects. Stop using sumatriptan and call your doctor at once if you have:

• sudden and severe stomach pain and bloody diarrhea;

• severe chest pain, shortness of breath, irregular heartbeats;

• a seizure (convulsions);

• blood circulation problems in your legs or feet--cramps, tight or heavy feeling, numbness or tingling, muscle weakness, burning pain, cold feeling, color changes (pale or blue), hip pain;

• heart attack symptoms--chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating;

• high levels of serotonin in the body--agitation, hallucinations, fever, fast heart rate, overactive reflexes, nausea, vomiting, diarrhea, loss of coordination, fainting;

• increased blood pressure--severe headache, blurred vision, pounding in your neck or ears, anxiety, nosebleed; or

• signs of a stroke--sudden numbness or weakness (especially on one side of the body), sudden severe headache, slurred speech, problems with vision or balance.

Common side effects of Imitrex may include:

• numbness, tingling, warmth, redness, or burning sensation;

• pressure or heavy feeling in any part of your body;

• dizziness, drowsiness, feeling weak or tired;

• neck pain or stiffness; or

• pain or redness where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Using sumatriptan while you are using certain other medicines can cause high levels of serotonin to build up in your body, a condition called "serotonin syndrome," which can be fatal. Tell your doctor if you also use:

• medicine to treat depression or a psychiatric disorder;

• medicine for Parkinson's disease;

• medicine for serious infections;

• herbal products;

• stimulant medicine;

• opioid medicine; or

• medicine to prevent nausea and vomiting.

This list is not complete. Other drugs may affect sumatriptan, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.