Imigran tablets contain the active ingredient sumatriptan, which is a type of medicine called a serotonin (or 5HT) agonist. This type of medicine is also commonly known as a 'triptan'. It is a painkiller specifically used to relieve migraine attacks.
Although the cause of migraine attacks is not fully understood, it is thought that widening of blood vessels in the brain causes the throbbing pain of migraine headaches. Sumatriptan relieves this pain by causing the blood vessels in the brain to narrow.
Sumatriptan works by stimulating receptors called serotonin (or 5HT) receptors that are found in the brain. A natural substance called serotonin normally acts on these receptors, causing blood vessels in the brain to narrow. Sumatriptan mimics this action of serotonin by directly stimulating the serotonin receptors in the brain. This narrows the blood vessels and so relieves the pain of migraine headaches.
It is best if sumatriptan can be taken as early as possible after the migraine headache has started, though it is also effective if taken at a later stage during the migraine attack.
Before you start taking Imigran (sumatriptan), read the manufacturer's printed information leaflet from inside the pack. It will give you more information about sumatriptan. It will also provide you with a step-by-step guide and diagrams to show you how to use the preparation you have been supplied with. If you are still unsure what to do, ask your pharmacist for further advice.
Take sumatriptan exactly as it states on the label of the pack.
Take one (50 mg or 100 mg) tablet with a drink of water, as soon as the headache phase develops. Or, if you prefer, you can take the tablet stirred into a small amount of water.
If your migraine at first improves but then comes back, you may take a further dose, providing it is at least two hours after the initial dose. If the first tablet has no effect, do not take a second dose for the same attack, as it is unlikely to work.
Medicines and their possible side effects can affect individual people in different ways. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect. The following are some of the side effects that are known to be associated with Imigran (sumatriptan):
Common (affect between 1 in 10 and 1 in 100 people):
- Sensation of tightness, pressure, tingling, heaviness, heat or pain in any part of the body, including the chest and throat (see warning above).
- Increase in blood pressure.
- Shortness of breath.
- Nausea and vomiting (though these may also be due to the migraine).
Very rare (affect less than 1 in 10,000 people):
- Visual disturbances such as flickering, reduced vision, double vision or loss of vision (though these may also be due to the migraine).
- Stiff neck.
- Increased or decreased heart rate (tachycardia or bradycardia).
- Awareness of your heart beat (palpitations).
- Irregular heart beats.
- Chest pain
- Heart attack.
- Alteration in results of liver function tests.
- Narrowing of the blood vessels in the hands leading to periods of white, painful hands (Raynaud's phenomenom).
- Low blood pressure (hypotension).
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
Imigran should be used with caution in:
- Allergy to medicines from the sulphonamide group, eg the antibiotic sulfamethoxazole.
- Controlled high blood pressure (hypertension).
- People with risk factors for ischaemic heart disease, such as smoking, high cholesterol levels, diabetes, obesity, or a family history of heart disease.
- Men over 40 years.
- Postmenopausal women.
- Decreased kidney function.
- Decreased liver function.
- History of seizures e.g. epilepsy, or people with conditions that increase the risk of seizures, e.g. head injury, alcoholism.
Imigran should NOT be used in:
- People who have had a heart attack.
- Heart disease caused by inadequate blood flow to the heart (ischaemic heart disease), e.g. angina.
- A severe form of angina pectoris, not caused by exertion (Prinzmetal's angina).
- Narrowing of blood vessels in the extremities, e.g. legs (peripheral vascular disease).
- History of stroke.
- History of small temporary strokes (transient ischaemic attacks).
- Uncontrolled or moderate to severe high blood pressure (hypertension).
- Severely decreased liver function.
- People who have taken a monoamine-oxidase inhibitor antidepressant (MAOI) in the last 14 days.
- A form of migraine associated with paralysis of the eye muscles (ophthalmoplegic migraine).
- A form of migraine associated with temporary paralysis of one side of the body (hemiplegic migraine).
- A type of migraine where there is a disturbance in brain function which initially presents with total blindness followed by dizziness, speech disturbances, ringing in the ears and double vision (basilar migraine).
- Imigran tablets are not recommended for adults aged over 65 years, as the safety and efficacy of the tablets have not been established.
- Imigran tablets contain lactose and should not be taken by people with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.
This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
The patient information leaflet (PIL) is a leaflet containing specific information about medical conditions, doses and side effects. You can download a copy of the PIL here:
Patient Info Leaflet