Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Imitrex Nasal (Sumatriptan-nasal). If you are concerned about side effects, discuss the risks and benefits of Imitrex Nasal (Sumatriptan-nasal) with your doctor.

The following side effects have been reported by at least 1% of people taking Imitrex Nasal (Sumatriptan-nasal). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• burning, discharge, pain, or soreness in the nose (nasal spray)
• burning, pain, or redness at place of injection (injectable form only)
• change in taste sensation
• dizziness
• drowsiness
• feelings of (in any part of the body):
• burning
• coldness
• heat
• heaviness
• numbness
• pressure
• strangeness
• tightness
• tingling
• warmth
• weakness
• flushing
• nausea
• tiredness
• vomiting
• weakness

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• loss of colour in fingers or toes
• shaking, tremors, or uncontrolled movements
• skin rash, Hives, itching, or bumps on skin
• slow, fast, or pounding heartbeat
• unusually cold hands or feet
• vision changes (usually temporary)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• convulsions (seizures)
• fast or irregular breathing
• irregular heartbeat
• loss of vision
• lower abdominal pain or severe rectal bleeding (blood in the stool or black, tarry stools)
• persistent purple discoloration of hands and feet
• Anaphylaxis (severe allergic reaction) (e.g., swelling of the face or throat, hives, difficulty breathing)
• signs of a heart attack (symptoms include pain, pressure, tightness, or heaviness in the chest, jaw, neck, or shoulder; sweating; or shortness of breath)
• signs of a stroke (e.g., sudden numbness or weakness, especially on one side of the body; sudden confusion or problems with speech; sudden vision problems in one or both eyes; sudden dizziness or loss of coordination; sudden severe headache, especially if it seems different from your usual headaches)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Imitrex Nasal (Sumatriptan-nasal).

Injection

Nasal Spray

5 mg
Each unit dose spray contains sumatriptan (base) as the hemisulfate salt 5 mg in an aqueous buffered solution. Nonmedicinal ingredients: anhydrous dibasic sodium phosphate, monobasic potassium phosphate, purified water, sodium hydroxide, and sulfuric acid.

20 mg
Each unit dose spray contains sumatriptan (base) as the hemisulfate salt 20 mg in an aqueous buffered solution. Nonmedicinal ingredients: anhydrous dibasic sodium phosphate, monobasic potassium phosphate, purified water, sodium hydroxide, and sulfuric acid.

Do not use sumatriptan if you:

• are allergic to sumatriptan or any ingredient of the medication
• are taking monoamine oxidase (MAO) inhibitors (e.g., Phenelzine, Tranylcypromine) or have taken them within the past 2 weeks
• do not have a clear diagnosis of migraine
• have Angina (chest pain), including Prinzmetal's angina (coronary vasospasm)
• have blood vessel disease (e.g., ischemic bowel disease, Raynaud's syndrome, Stroke, transient ischemic attacks [TIAs])
• have certain types of migraine headaches (including hemiplegic, basilar, or ophthalmoplegic migraine)
• have had a Heart Attack
• have heart disease (e.g., heart valve disease, ischemic heart disease, abnormal heart rhythms, congenital heart disease)
• have high blood pressure that is severe or not under control
• have severely reduced liver function
• have taken another 5-hydroxytryptamine agonist (i.e., Naratriptan, Rizatriptan, Zolmitriptan) in the previous 24 hours
• have taken ergotamine-containing or ergot-type medications (such as Dihydroergotamine, ergotamine, or methysergide) in the previous 24 hours

There may be an interaction between sumatriptan and any of the following:

• amphetamines (e.g., Dextroamphetamine, Lisdexamfetamine)
• anti-psychotics (e.g., Chlorpromazine, Clozapine, Haloperidol, Olanzapine, Quetiapine, Risperidone)
• Bromocriptine
• Buspirone
• Cabergoline
• Cyclobenzaprine
• Dextromethorphan
• ergot-containing medications (e.g., dihydroergotamine, ergotamine, or methysergide), if taken at the same time or within the previous 24 hours
• Linezolid
• lithium
• monoamine oxidase inhibitors (M.O.S. e.g., Moclobemide, Rasagiline, Selegiline, tranylcypromine), if taken at the same time or within 14 days of taking sumatriptan
• Meperidine
• Methadone
• methylene blue
• Methylphenidate
• Metoclopramide
• Mirtazapine
• other 5-hydroxytryptamine agonists (e.g., rizatriptan, naratriptan, zolmitriptan), if taken at the same time or within the previous 24 hours
• narcotic pain relievers (e.g., Codeine, Fentanyl, Morphine, Oxycodone)
• nefazodone
• rasagiline
• selegiline
• St. John's wort
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, Sertraline)
• serotonin antagonists (anti-emetic medications; e.g., Granisetron, Ondansetron)
• serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., Desvenlafaxine, Duloxetine, venlafaxine)
• Tapentadol
• Tramadol
• Trazodone
• tricyclic antidepressants (e.g., Amitriptyline, Doxepin, Imipramine, Nortriptyline)
• Tryptophan

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Imitrex Nasal (Sumatriptan-nasal). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Imitrex Nasal (Sumatriptan-nasal).

Allergy: If you are allergic to sulphonamides (sulfa medications) you may experience an allergic reaction to sumatriptan. Reactions range from a skin allergy to a serious allergic reaction. If you are allergic to other medications in this class (5-hydroxytryptamine agonists such as rizatriptan and naratriptan) you can also have an allergic reaction to sumatriptan. If you are allergic to any of these medications, you should not take sumatriptan unless advised to do so by your doctor.

Blood pressure: Sumatriptan may cause an increase in blood pressure. If you have severe or uncontrolled high blood pressure, do not take sumatriptan.

Drowsiness/reduced alertness: Drowsiness may occur as a result of taking Imitrex Nasal (Sumatriptan-nasal). Avoid driving, operating machinery, or performing other hazardous tasks until you have determined how Imitrex Nasal (Sumatriptan-nasal) affects you.

Heart disease: Imitrex Nasal (Sumatriptan-nasal) may cause narrowing of the blood vessels that supply the heart. This can lead to chest pain, heart attacks, and other heart problems. For this reason, sumatriptan should not be used by people with heart or blood vessel disease. If you have certain risk factors for heart disease (e.g., high blood pressure, High Cholesterol, smoking, Obesity, Diabetes, family history of Coronary Artery Disease, Menopause, men over 40 years of age), tell your doctor. If you experience symptoms of a heart attack (e.g., pain, pressure, tightness, or heaviness in the chest, jaw, neck, or shoulder; sweating; or shortness of breath), get immediate medical attention.

Injection: The injectable form of sumatriptan should never be taken intravenously (into a vein).

Kidney function: The effect of reduced kidney function on how sumatriptan acts in the body has not been evaluated. Sumatriptan is not recommended for use if you have reduced kidney function.

Liver function: Liver disease or reduced liver function may cause Imitrex Nasal (Sumatriptan-nasal) to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how Imitrex Nasal (Sumatriptan-nasal) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Imitrex Nasal (Sumatriptan-nasal), and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking Imitrex Nasal (Sumatriptan-nasal).

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

A lower dose of sumatriptan may be needed for people with reduced liver function. However, sumatriptan is not recommended for use if you have severely reduced liver function.

Medication overuse headaches: As with other pain relief medications, overuse of sumatriptan may lead to medication overuse headaches, or "rebound headaches" where the headache returns as the medication wears off. Avoid taking more of Imitrex Nasal (Sumatriptan-nasal) than is recommended by your doctor. If you experience more frequent headaches, contact your doctor as soon as possible.

Seizures: There have been rare reports of seizures experienced by people taking Imitrex Nasal (Sumatriptan-nasal). Most of these people had a previous history of Epilepsy or medical conditions that increase the risk of seizures. If you have a history of epilepsy or other condition that increases your risk for seizure, discuss with your doctor how Imitrex Nasal (Sumatriptan-nasal) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Imitrex Nasal (Sumatriptan-nasal), and whether any special monitoring is needed.

Serotonin syndrome: People who use sumatriptan along with serotonin reuptake inhibitors (SSRIs; e.g., Paroxetine, Citalopram, Fluoxetine), serotonin norepinephrine reuptake inhibitors (SNRIs; e.g., Venlafaxine), or other medications that act on serotonin, may experience serotonin syndrome. This syndrome is severe and can be life-threatening. If you are taking antidepressants, discuss with your doctor how Imitrex Nasal (Sumatriptan-nasal) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Imitrex Nasal (Sumatriptan-nasal), and whether any special monitoring is needed.

If you experience symptoms of serotonin syndrome (e.g., agitation, hallucinations, fast heartbeat, Fever, increased reflexes, nausea, vomiting, Diarrhea) after using sumatriptan, get immediate medical attention.

Stroke and bleeding around the brain: Rarely, Imitrex Nasal (Sumatriptan-nasal) may cause cerebrovascular events such as stroke and bleeding around the brain. If you have had a previous stroke or are at risk for it, talk to your doctor about the use of Imitrex Nasal (Sumatriptan-nasal). If you experience signs and symptoms of a stroke (e.g., sudden numbness or weakness, especially on one side of the body; sudden confusion or problems with speech; sudden vision problems in one or both eyes; sudden dizziness or loss of coordination; sudden severe headache, especially if it seems different from your usual headaches), get immediate medical attention.

Pregnancy: Imitrex Nasal (Sumatriptan-nasal) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Imitrex Nasal (Sumatriptan-nasal), contact your doctor immediately.

Breast-feeding: Imitrex Nasal (Sumatriptan-nasal) passes into breast milk. If you are a breast-feeding mother and are taking sumatriptan, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children and adolescents: The safety and effectiveness of Imitrex Nasal (Sumatriptan-nasal) have not been established for adolescents and children under 18 years of age.

Seniors: There is limited experience with the use of sumatriptan by people over 65 years of age. The use of Imitrex Nasal (Sumatriptan-nasal) by seniors is not recommended.