What is Sumatriptan?

Sumatriptan is the most widely used migraine treatment in the UK, and also the one most often taken incorrectly. This page covers how it actually works, how to dose it, and which of the commonly repeated interaction warnings are real.

Most descriptions of sumatriptan stop at "it narrows blood vessels in the brain". That is some of its mechanism of action but not all of it.

Sumatriptan is a selective agonist at 5-HT1 receptors and has no meaningful activity at the other serotonin receptor subtypes.

In the cranial blood vessels 5-HT1 receptors produce vasoconstriction, narrowing vessels in the carotid vascular bed that supplies the meninges. On the trigeminal nerve 5-HT1 receptors suppress the nerve activity that drives the pain signalling of an attack.

Acting on these receptors is why sumatriptan works on migraine but ordinary blood vessel medicines do not, and it is why the newer migraine drugs target the nerve side of the mechanism directly.

It is important to know sumatriptan is not a preventer, it will not stop another attack, and it should not be taken on a regular schedule. If you are having frequent attacks, the answer is a preventive medicine, not to keep taking sumatriptan daily.^[1]

The recommended dose is a single 50mg tablet, increasing to 100mg if needed. Doses between 25mg and 100mg all beat placebo in trials, but 25mg is significantly less effective than the two higher doses, so there is little reason to use it. A clinical response usually appears around 30 minutes after an oral dose.

Take it as early in the attack as you can. Taking it early is about getting relief sooner rather than about the drug working better.

The thing people struggle with when taking sumatriptan is what to do when a tablet doesn't seem to touch it. There are two different situations and they have opposite answers.

The headache never responded. Do not take a second tablet for that attack. If the first dose did nothing, a second one will not either. Treat that attack with paracetamol, aspirin or an NSAID instead, and sumatriptan can still be used for your next attack.

The headache responded and then came back. A second dose can be taken within the same 24 hours, as long as at least 2 hours have passed since the first. No more than 300mg in any 24-hour period.^[1]

Most people take sumatriptan without trouble. The most common effects are dizziness, drowsiness, tingling or altered sensation, flushing, breathlessness, nausea and vomiting, muscle aches, and a transient rise in blood pressure shortly after the dose.

Sumatriptan commonly causes sensations of heaviness, pressure, tightness, heat or cold, which can be intense and can affect any part of the body including the chest and throat; these usually only last a short while. If there is any suggestion it reflects heart disease such as chest tightness, stop taking sumatriptan and contact a healthcare professional or 111 for advice.

Rarer but serious effects include coronary artery spasm, angina, myocardial infarction, arrhythmias, seizures, and visual disturbance including, very rarely, permanent visual loss.

If you are allergic to sulphonamide antibiotics, mention it before taking sumatriptan. Cross-reactivity evidence is limited, but reactions have ranged from skin rash to anaphylaxis.^[1]

Stop taking sumatriptan and speak to a pharmacist, your prescriber or your GP if you notice:

1. Chest pain or tightness that is severe, lasts beyond a few minutes, or spreads to the arm or jaw
2. A racing, slow or irregular heartbeat
3. Any change in your vision that does not settle when the attack passes
4. Weakness, numbness or difficulty speaking, particularly on one side
5. Agitation, confusion, shivering, sweating, muscle twitching or a fast heartbeat after starting a new medicine alongside it
6. Severe stomach pain with bloody diarrhoea

If you have chest pain, severe breathlessness, or stroke-like symptoms, treat it as an emergency and call 999.

Sumatriptan should not be taken if you have:

1. Had a heart attack, or have ischaemic heart disease, coronary vasospasm (Prinzmetal's angina) or peripheral vascular disease
2. Had a stroke or a transient ischaemic attack
3. Moderate or severe high blood pressure, or mild high blood pressure that is not controlled
4. Severe liver impairment
5. Taken an MAOI within the last two weeks
6. Taken ergotamine or another triptan recently (see below)

Should be taken with extra caution if you suffer with:

1. Kidney problems. Reduced kidney function is a reason for care, not a bar. Severe liver impairment is the contraindication, and mild to moderate liver impairment means using 25mg to 50mg.
2. A history of seizures. Seizures have been reported with sumatriptan, so it needs a considered decision, but epilepsy does not automatically rule it out.
3. Mild controlled hypertension. Can cause blood pressure to rise transiently after a dose.
4. Risk factors for heart disease such as heavy smoking or nicotine replacement, particularly in post-menopausal women and men over 40. These need a cardiovascular assessment first.
5. Age. Not recommended under 18 or over 65, in both cases because the evidence is not there rather than because of a specific known harm.

Sumatriptan is also not the right treatment for hemiplegic, basilar or ophthalmoplegic migraine, and it should only be used where migraine has actually been diagnosed.^[1]

1. Paracetamol and NSAIDs. Both work on a different pathway and can be combined with sumatriptan. They are especially recommended when a sumatriptan dose has failed to work for an attack.
2. Anti-sickness medicines. If nausea is a significant part of your attacks, prochlorperazine can be used alongside sumatriptan.
3. Common migraine preventers. There is no evidence of interaction with propranolol, pizotifen or flunarizine.

1. Another triptan, or ergotamine. Contraindicated together. Wait at least 24 hours after ergotamine or another triptan before taking sumatriptan. Wait at least 6 hours after sumatriptan before an ergotamine product, and at least 24 hours before a different triptan.
2. MAOIs. Contraindicated, including for two weeks after stopping one.
3. Lithium. Carries a risk of serotonin syndrome in combination.
4. St John's Wort. Side effects occur more frequently when triptans are taken with it.
5. SSRIs and SNRIs. Serotonin syndrome with a triptan plus an SSRI or SNRI has been reported, but only rarely and only through post-marketing reports, which cannot establish how often it happens or whether the triptan caused it. The combination can be taken but must be taken with caution.

Taking any headache treatment too frequently can make headaches worse rather than better. If you're getting frequent or daily headaches despite regular use of headache medicines, you may want to contact your GP to discuss your medicine and headaches. Especially if your attacks get more frequent which causes you take more tablets more frequently, and the pattern reinforces itself. If you find your sumatriptan use has been creeping up, contact your GP to have a conversation about prevention.

Sumatriptan 50mg is both a P-medicine and a prescription-only medicine. It does come as a single pharmacy pack containing two 50mg tablets, which is available as a pharmacy (P) medicine for people with an established migraine diagnosis, any larger packs require a prescription.