Sumatriptan: Side Effects, Interactions, Dosage & Warnings

A box of torrent branded 100mg sumatriptan leaning on a box of 50mg sumatriptan tablets
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What is Sumatriptan and what is it used for?

Sumatriptan is a migraine treatment belonging to a class of drugs known as ‘triptans’, also known as 5-hydroxytryptamine receptors. It is also referred to as its brand name, Imigran. Sumatriptan is available as a 50mg and 100mg strength. In the UK, you can buy sumatriptan over the counter in the 50mg strength, but you are limited to two tablets. If you require more than two tablets or the 100mg strength, you require a prescription from a doctor. It is available as a tablet or nasal spray (the faster acting option). This medication is only licensed to treat a migraine once it has started and cannot prevent a migraine.


How it works

Sumatriptan tablets work by temporarily narrowing blood vessels in the brain, preventing pain signals from being sent. It also works to inhibit the release of natural chemicals which cause migraine symptoms such as pain and nausea. Sumatriptan will only work to relieve a migraine once it has started and does not work to prevent or reduce the frequency of migraines.

How long does it take to work?

Sumatriptan tablets usually work within 30-60 minutes and the nasal spray and injections usually work within 15 minutes. Whilst these tablets are effective, there is no guarantee that they will work every time. If it is not effective for you, there are alternatives that belong to the same class of drugs that can be effective.


Sumatriptan dosage

Sumatriptan is available as a 50mg and 100mg tablet. The recommended starting dose is usually 50mg, and 100mg is used where patients do not experience full relief with 50mg.

How to take Sumatriptan

Take one 50mg or 100mg with a glass of water at the onset of a migraine. You should swallow tablets whole and not crush them, although some tablets that are scored down the middle can be split in those that have trouble swallowing tablets. Some people experience ‘aura’ (visual disturbances, tingling sensation, dizziness, difficulty speaking, loss of consciousness) before a migraine attack. You should not take a tablet if you experience aura without a migraine. If you experience relief with sumatriptan, you can take another tablet after 2 hours. However, if the first dose does not help, do not take another tablet.

You can take sumatriptan with or without food and you should avoid crushing the tablet.

How often can I take Sumatriptan?

The maximum dose of sumatriptan within a 24-hour period is 300mg. Do not exceed this dose as it may cause narrowing of the blood vessels which can lead to heart complications.


Sumatriptan side effects

As with all medication, sumatriptan is associated with side effects such as drowsiness.

Common side effects

Common side effects of sumatriptan typically affect up to 10% of users. They include:

  • Dizziness
  • Drowsiness
  • Lethargy
  • Tightness or pressure in the chest
  • Feeling cold or warm
  • Heaviness
  • Tingling
  • Flushing
  • Vomiting
  • Muscle ache

Side effects are temporary and usually pass. If side effects continue or get worse (especially difficulty breathing), seek urgent medical attention.


Side effects of Sumatriptan nasal spray

The nasal spray can have the same effects as the tablets and can also cause the following:

  • Burning or irritation in your throat or nose
  • Nose bleeds
  • Bad taste in your throat


When to avoid Sumatriptan


You should not take sumatriptan tablets if you are taking certain medication. These include:

  • Selective Serotonin Reuptake Inhibitors (SSRIs) or Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs). These include duloxetine, venlafaxine, citalopram, escitalopram, fluoxetine, sertraline, paroxetine, vortioxetine. These are antidepressants that can cause serotonin syndrome, when taken with sumatriptan. Symptoms of serotonin syndrome include sweating, confusion, restlessness, hallucinations, muscle spasms, increased heart rate, diarrhoea, shivering and shaking.
  • Monoamine Oxidase Inhibitors (MAOIs) such as rasagiline, selegiline, isocarboxazid, phenelzine, tranylcypromine can also cause serotonin syndrome and increase the exposure to sumatriptan.
  • Drugs that contain Ergot such as ergotamine cause blood vessels to constrict, which can cause symptoms such as a tight chest. You should stop taking these drugs 24 hours before using sumatriptan and wait 6 hours after taking sumatriptan before you take ergotamine again.
  • St John’s Wort which is a herbal remedy to treat depression. Taking sumatriptan and St john’s wort can increase the chances of side effects.



You should not use sumatriptan if you:

  • Are under the age of 18, or over the age of 65. It is not licensed for use in people who fall outside of this age bracket.
  • Have heart problems such as angina, or a history of a heart attack. Sumatriptan can cause a disruption to the rhythm of your heart. It can also cause very serious heart problems and those with heart conditions are usually advised to avoid this medication, unless this is under the supervision of your doctor.
  • Have circulation issues in your legs that causes cramps when you walk (peripheral vascular disease). Sumatriptan can worsen circulation issues and you should avoid using this medication.
  • Have had a stroke. Sumatriptan can cause a brain haemorrhage (bleeding in the brain) or stroke.
  • Have high blood pressure (you can use sumatriptan if you are taking medication to treat high blood pressure and it is under control). Sumatriptan can raise blood pressure and you should not use this medication if your blood pressure is not under control.
  • Have liver disease which is serious
  • Are using other medication to treat migraine. There is a serious interaction between ergotamine, another medication that treats migraines. Other migraine medication such as zolmitriptan and rizatriptan belong to the same class of drugs as sumatriptan. Taking these medications together can cause an overdose.
  • Suffer from seizures. It increases the likelihood of experiencing a seizure.

Sumatriptan can cause heart complications in a small number of people. If you fall into the following categories, you should discuss the use of sumatriptan with your doctor:

  • If you are a smoker; and especially
  • If you are a male over the age of 40
  • If you are a female who has been through menopause

If you fall into two of these categories, you may need to have your heart function tested, as you are at a higher risk of developing heart disease. This can cause complications.


Allergy warning

If you have an allergy to antibiotics known as sulphonamides, you may be allergic to sumatriptan.

The following symptoms are typical of an allergic reaction, and if you develop these symptoms after taking sumatriptan, you may be allergic. You should seek urgent medical attention if you develop the following symptoms:

  • Rash
  • Itchy skin (hives)
  • Wheezing or difficulty breathing
  • Swelling of the face including eyelids, lips and tongue
  • Collapse


Taking Sumatriptan whilst pregnant

If you are pregnant and wish to take sumatriptan, you should discuss this with your doctor. There is limited research that looks at the safety of sumatriptan in pregnant women. Your doctor will weigh up the benefits, against the potential negative outcomes.


Taking Sumatriptan whilst breastfeeding

Sumatriptan is present in breast milk and you should leave a 12-hour gap between taking sumatriptan and breastfeeding. You should contact your doctor and let them know if you wish to take this drug when breastfeeding.


Sumatriptan and alcohol

Alcohol does not affect sumatriptan and how it works. However, alcohol can trigger migraines and may make them worse, so you should avoid alcohol when suffering from a migraine.

Whilst all of our content is written and reviewed by healthcare professionals, it is not intended to be substituted for or used as medical advice. If you have any questions or concerns about your health, please speak to your doctor.