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Imitrex dosage, forms, and strengths

Medically reviewed by Anne Jacobson, MD, MPH
Board-Certified Family Physician
Updated Sep 13, 2021  •  Published Aug 3, 2021
Fact Checked

Imitrex is a brand-name prescription drug that helps to relieve migraine and cluster headaches. The active ingredient, sumatriptan succinate, belongs to a family of drugs called triptans (or 5-HT receptor agonists) and works by causing blood vessels in the head to constrict, relieving many of the symptoms of migraine or cluster headache. Imitrex can be taken as a tablet, nasal spray, or injection. All work differently, so the method prescribed will depend on each individual’s condition.

RELATED: Learn more about Imitrex | Get Imitrex discounts

Imitrex forms and strengths

Each form of Imitrex—tablets, injections, or nasal spray—varies in the amount of drug that makes it into the bloodstream. As a result, the different dosage forms have significantly different dosing strengths.

  • Tablets: 25 milligrams (mg), 50 mg, 100 mg

  • Nasal spray: 5 mg, 10 mg, 20 mg

  • Injection (StatDose Pen): 4 mg, 6 mg

Imitrex nasal spray is packaged in individual nasal spray units containing a single dose. Injections are packaged as injector pen cartridges each containing a single dose. 

Imitrex dosage for adults

Imitrex dosage chart
Indication Form Starting dosage Standard dosage Maximum dosage
Migraine Tablet 25–100 mg  25–100 mg tablet followed by a second dose if necessary no sooner than 2 hours later 200 mg in 24 hours
Nasal spray 5–20 mg 5–20 mg single nasal spray followed by a second dose if necessary no sooner than 2 hours later 40 mg in 24 hours
Pen auto-injector 4–6 mg 4–6 mg subcutaneous injection followed by a second dose if necessary no sooner than 1 hour later 12 mg in 24 hours
Cluster headache Pen auto-injector 4–6 mg  4–6 mg subcutaneous injection followed by a second dose if necessary no sooner than 1 hour later 12 mg every 24 hours

Imitrex dosage for migraine

Imitrex tablets, nasal spray, and injections are FDA approved as an acute treatment of migraine with or without aura. Migraine headaches are triggered by a variety of factors and are a complex phenomenon involving overexcitement of nerve cells and dilation of blood vessels in the head. The dilation of blood vessels causes many of the symptoms of a migraine. Sumatriptan narrows those blood vessels, thus relieving migraine symptoms.

Imitrex dosage forms vary in their effects. About 14%–17% of the sumatriptan in a tablet or nasal spray dose makes it into the bloodstream. The nasal spray, though, starts working sooner—in about 15 minutes—rather than 30–60 minutes for a tablet. On the other hand, almost all of an injection dose enters the bloodstream, begins working in minutes, and produces a much higher peak concentration than either tablets or nasal spray. 

  • Standard dosage for migraine (tablets): 25–100 mg dose tablet followed by a seconddose if necessary no sooner than two hours later

  • Standard dosage for migraine (nasal spray): 5–20 mg dose followed by a second dose if necessary no sooner than two hours later

  • Standard dosage for migraine (injection): 4–6 mg dose followed by a second dose if necessary no sooner than one hour later

  • Maximum dosage for migraine (tablets): 200 mg per 24-hour period

  • Maximum dosage for migraine (nasal spray): 40 mg per 24-hour period

  • Maximum dosage for migraine (injection): 12 mg per 24-hour period

Imitrex dosage for cluster headache

Imitrex injections are approved to treat acute cluster headaches. As with migraines, sumatriptan relieves the symptoms of cluster headache by constricting blood vessels in the head and face. 

  • Standard dosage for cluster headache (injection): 4–6 mg dose followed by a second dose if necessary no sooner than one hour later

  • Maximum dosage for cluster headache (injection): 12 mg per 24-hour period

Imitrex dosage for children

Imitrex is only approved for use in adults 18 years and older, though some healthcare professionals may use Imitrex injections off-label as an acute treatment of migraine in children.

Imitrex dosage restrictions

For a variety of reasons, Imitrex may not be the right medication for some people. Contraindications include ischemic coronary artery disease, heart attack, angina pectoris, some forms of irregular heartbeat, history of stroke or transient ischemic attack (TIA), hemiplegic or basilar migraines, peripheral vascular disease, ischemic bowel disease, uncontrolled hypertension, severe liver impairment, or severe hypersensitivity to the drug. People with renal impairment, mild to moderate liver impairment, and the elderly do not require a dose adjustment but should use Imitrex with caution. Caution is also required in those with seizure disorders, high blood pressure, latex allergy (if using the injectable form), and cardiac risk factors. 

How to take Imitrex

Imitrex is taken as a tablet, nasal spray, or self-administered subcutaneous injection. Doses will vary between these different formats.

  • Read and follow the patient instructions that come with this medicine.

  • If you do not get any relief from the first dose, do not take a second dose without first talking to a doctor or other healthcare provider.

  • If you get some relief from the first dose, but the migraine returns or the first dose does not provide enough relief, wait for at least one hour (injection) or two hours (tablets or nasal spray) before taking a second dose.

  • If more than two doses are required in a single day, do not take additional doses. Call a doctor or other healthcare professional for medical advice.

Imitrex tablets

  • Imitrex tablets can be taken with or without food

  • Swallow

    Imitrex tablets whole with a glass of water or other liquid

Imitrex nasal spray

  1. The Imitrex nasal spray unit delivers a single dose

  2. Imitrex nasal spray is administered into one nostril only

How to take nasal spray:

  1. Before using, blow your nose to clear the nasal passages.

  2. Insert the nozzle into the open nostril and close your mouth.

  3. Press the blue plunger while breathing in through the open nostril.

  4. Remove the nozzle and, facing forward, gently breathe in through the nose and out through the mouth for 10–20 seconds.

Imitrex STATdose injection

  • The STATdose pen injects a single dose of Imitrex

  • A healthcare professional will demonstrate how to use the STATdose cartridges and pen injector

  • The STATdose injector comes in a carrying case for both the pen injector and medicine cartridges

  • The carrying case contains only two doses. Do not use more than one carrying case (two doses) per day

How to take injection:

  1. Have a healthcare professional demonstrate the correct injection technique before taking the first dose.

  2. Carefully follow the instructions on the package insert.

  3. Properly dispose of used cartridge packs.

Imitrex dosage FAQs

How long does it take Imitrex to work?

Imitrex injections will begin to work in about six minutes and the medicine reaches its peak concentration in the blood in about 12 minutes. In contrast, Imitrex nasal spray begins working in about 15 minutes while the tablet takes about 30 minutes with a peak concentration in about 45 minutes. However, migraine-induced gastroparesis (delayed gastric emptying) could delay the tablet’s effectiveness by another 30 minutes.

How long does Imitrex stay in your system?

With a half-life of close to two hours, Imitrex is short-acting and quickly cleared from the body. Some people experience a return of migraine symptoms when the first dose wears off, so a second dose may be needed.

What happens if I miss a dose of Imitrex?

Imitrex is usually taken at the onset of migraine or cluster headache symptoms but can be administered at any time during a cluster headache or migraine attack. A second dose can be administered after two hours if symptoms only partially resolve or the headache returns. Do not take a second dose if the first dose provides no noticeable relief and contact a healthcare provider.

How do I stop taking Imitrex?

Used as directed, Imitrex can be safely discontinued without problems. However, using Imitrex too frequently—10 or more days a month—can cause medication-overuse headache (MOH), a condition in which the frequency and intensity of headaches increases when using too much headache medication. Fortunately, stopping sumatriptan does not cause withdrawal symptoms other than rebound headache and possibly nausea or sleep problems. These fade in about four days. A doctor may choose to stop the medication completely or use a steadily decreasing dose.

In addition to medical-overuse headache, a healthcare professional may choose to end sumatriptan treatment at any sign of heart problems, such as chest pain (angina), chest tightness, or shortness of breath. Imitrex will also be discontinued in case of stroke, transient ischemic attack, or a severe allergic reaction. If sumatriptan is discontinued, alternative therapies include other triptans, ergot drugs, pain relievers, CGRP antagonists, anti-nausea drugs, dexamethasone, or a range of physical treatments. 

Other side effects of Imitrex can include nausea, dizziness, drowsiness, vomiting, spinning sensation, and sensitivity to light or sound. If you experience any of these side effects after taking Imitrex, contact your healthcare professional. 

What is the maximum dosage for Imitrex?

The maximum daily dose for Imitrex is two 100 mg tablets, two 12 mg nasal sprays, or two 6 mg injections. Healthcare professionals will warn people not to take Imitrex 10 or more days per month.

What interacts with Imitrex?

Some Imitrex drug interactions can cause serious side effects including serotonin syndrome, vasospasms, or dangerously high blood pressure.

Imitrex should not be used within two weeks of taking an MAO inhibitor such as Marplan (isocarboxazid), phenelzine, tranylcypromine, selegiline, linezolid, or procarbazine.

Imitrex should not be taken within 24 hours taking other triptans such as Amerge (naratriptan), Axert (almotriptan), rizatriptan, or Treximet (sumatriptan and naproxen), or ergot migraine drugs such as ergotamine and dihydroergotamine.

Serotonin syndrome, a neurological condition caused by excess serotonin in the brain, is also a risk when Imitrex is taken with antidepressants, particularly SSRIs (such as fluoxetine) and SNRIs (such as venlafaxine). 

Is it safe to take Imitrex during pregnancy?

The safety of taking Imitrex while pregnant has not been definitively established. Clinical studies, however, have not shown an increase in birth defects in pregnant mothers taking sumatriptan. Nursing mothers are cautioned to avoid breastfeeding for 12 hours after taking a sumatriptan dose. Sumatriptan does pass into breast milk when taken during lactation. Before starting Imitrex, inform your healthcare provider if you are pregnant, may become pregnant, or are breastfeeding.

Medically reviewed by Anne Jacobson, MD, MPH
Board-Certified Family Physician

Anne Jacobson, MD, MPH, is a board-certified family physician, writer, editor, teacher, and consultant. She is a graduate of University of Wisconsin School of Medicine and Public Health, and trained at West Suburban Family Medicine in Oak Park, Illinois. She later completed a fellowship in community medicine at PCC Community Wellness and a master's in Public Health at the University of Illinois-Chicago. She lives with her family near Chicago.

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