SIDE EFFECTS: Flushing, feelings of tingling/numbness/prickling/heat, tiredness, weakness, drowsiness, or dizziness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. This medication may raise your blood pressure. Check your blood pressure regularly and tell your doctor if the results are high. Tell your doctor right away if you have any serious side effects, including: blue fingers/toes/nails, cold hands/feet, hearing changes, mental/mood changes. Sumatriptan can commonly cause chest/jaw/neck tightness, pain, or pressure that is usually not serious. However, these side effects are like symptoms of a heart attack, which may include chest/jaw/left arm pain, shortness of breath, or unusual sweating. Get medical help right away if these or other serious side effects occur, including: fast/irregular heartbeat, fainting, severe stomach/abdominal pain, bloody diarrhea, seizure, signs of a stroke (such as weakness on one side of the body, trouble speaking, sudden vision changes, confusion). This medication may increase serotonin and rarely cause a very serious condition called serotonin syndrome/toxicity. The risk increases if you are also taking other drugs that increase serotonin, so tell your doctor or pharmacist of all the drugs you take (see Drug Interactions section). Get medical help right away if you develop some of the following symptoms: fast heartbeat, hallucinations, loss of coordination, severe dizziness, severe nausea/vomiting/diarrhea, twitching muscles, unexplained fever, unusual agitation/restlessness. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before using sumatriptan, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: blood circulation problems (for example, in your legs, arms/hands, or stomach), certain types of headaches (hemiplegic or basilar migraine), heart problems (such as chest pain, irregular heartbeat, previous heart attack), liver disease, seizure, stroke or "mini-stroke" (transient ischemic attack). Certain conditions can increase your risk for heart problems. Tell your doctor if you have any of these conditions, including: high blood pressure, high cholesterol, diabetes, family history of heart disease, overweight, smoker, postmenopausal (women), age more than 40 years (men). This drug may make you dizzy or drowsy. Alcohol or marijuana can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana. Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). The risk of heart disease, liver disease, and high blood pressure increases with age. Older adults may be more sensitive to the side effects of this drug, especially increased blood pressure and heart problems. During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor. This drug passes into breast milk in small amounts. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Do not take any MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. Ask your doctor when to start or stop taking this medication. The risk of serotonin syndrome/toxicity increases if you are also taking other drugs that increase serotonin. Examples include street drugs such as MDMA/"ecstasy," St. John's wort, certain antidepressants (including SSRIs such as fluoxetine/paroxetine, SNRIs such as duloxetine/venlafaxine), among others. The risk of serotonin syndrome/toxicity may be more likely when you start or increase the dose of these drugs. If you also take any ergotamine medication (such as dihydroergotamine) or other "triptan" drugs (such as zolmitriptan, rizatriptan), you will need to separate your sumatriptan dose from your dose of these other medications to lessen the chance of serious side effects. Ask your doctor how long you should wait between your doses of these drugs.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.