How does it work?
Sabril tablets and sachets contain the active ingredient vigabatrin, which is a medicine used to treat epilepsy. It works by stabilising electrical activity in the brain.
The brain and nerves are made up of many nerve cells that communicate with each other through electrical signals. These signals must be carefully regulated for the brain and nerves to function properly. When abnormally rapid and repetitive electrical signals are released in the brain, it becomes over-stimulated and normal function is disturbed. This results in fits or seizures.
Vigabatrin works by affecting the activity of a neurotransmitter called GABA. Neurotransmitters are natural body chemicals that are stored in nerve cells. They are involved in transmitting messages between the nerve cells. GABA is a neurotransmitter that acts as a natural 'nerve calming' agent. It helps keep the electrical nerve activity in the brain in balance.
Vigabatrin prevents the breakdown of GABA in the brain. This enables GABA to calm the nerve activity in the brain for a longer period of time, which helps to prevent seizures.
Vigabatrin is used as an add-on treatment for people whose epilepsy has not been well controlled by, or who cannot take, other antiepileptic medicines. It is used to prevent partial seizures, and partial seizures that spread to secondary generalised seizures. Vigabatrin can also be used on its own to treat spasms in infants known as West's syndrome.
What is it used for?
- Epilepsy used as an add-on treatment for people with partial seizures with or without secondary generalisation.
- Infantile spasms (West's syndrome).
- The contents of Sabril sachets should be dissolved in at least 100ml of water or a soft drink, eg fruit juice or milk, immediately before taking.
- This medicine may cause drowsiness and visual problems that could reduce your ability to safely perform potentially hazardous tasks such as driving or operating machinery. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.
- You should tell your doctor if you feel extremely tired, sedated or confused after you start taking this medicine, as your dose may need reducing.
- There may be a small increased risk of suicidal thoughts and behaviour in people taking antiepileptic medicines such as vigabatrin for any condition. For this reason, it is very important to seek medical advice if you, or someone else taking this medicine, experience any abnormal thoughts or feelings during treatment, for example feeling agitated, irritable, depressed or paranoid, or have any distressing thoughts or feelings about suicide or self-harm at any point while taking this medicine. For more information speak to your doctor or pharmacist.
- This medicine can cause visual problems in about one third of people who take it. This can occur after months or years of taking the medicine and can be irreversible. For this reason, your eyesight will be checked before you start treatment and you will need to have regular eye examinations every six months while you are taking this medicine. You should let your doctor know immediately if you notice any change in your eyesight, for example reduced peripheral vision, while you are taking this medicine.
- If you have epilepsy it is important to take your medication regularly, as directed by your doctor, because missing doses can trigger seizures in some people. If you have trouble remembering to take your medicine you should ask your pharmacist for advice. You may find a pill reminder box helpful.
- You should not suddenly stop taking this medicine without consulting your doctor, as this may result in your seizures returning or getting worse. If it is decided that you should stop taking this medicine, the dose should usually be reduced gradually over two to four weeks. Follow the instructions given by your doctor.
- This medicine may cause movement disorders in children being treated for infantile spasms. If you notice new movement disorders, such as severe difficulty performing voluntary movements (dyskinesia), abnormal muscle tension (dystonia) or increased rigidity or spasticity of muscles during treatment with this medicine it is important to consult a doctor.
Use with caution in
- Elderly people.
- Decreased kidney function.
- History of mental disorders (psychoses).
- History of behavioural problems.
- History of depression.
Not to be used in
- People with significant eye problems that have impaired their field of vision, for example glaucoma.
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.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- It is very important for women with epilepsy to talk to the doctor responsible for their epilepsy treatment before becoming pregnant. Antiepileptic medicines are associated with an increased risk of developmental disorders and malformations in the baby. However, stopping antiepileptic treatment during pregnancy runs the risk of the mother having seizures, which can harm both the mother and the foetus. This risk may be higher than that from continuing the medication. It is important that all the risks and benefits of treatment are weighed up. Seek medical advice from your doctor.
- This medicine passes into breast milk. The manufacturer recommends that mothers who need treatment with this medicine should bottlefeed rather than breastfeed their babies. Seek medical advice from your doctor.
- Do not stop taking this medication except on your doctor's advice.
- This medication may cause drowsiness. If affected do not drive or operate machinery.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
Very common (affect more than 1 in 10 people)
- Visual field defects (loss of peripheral vision) see warning section above.
- Sleepiness or fatigue.
- Excitement or agitation in children.
Common (affect between 1 in 10 and 1 in 100 people)
- Weight gain.
- Concentration and memory difficulties.
- Speech problems.
- Pins and needles sensation.
- Eye disorders such as blurred or double vision, or twitching of the eyeball.
- Disturbances of the gut such as nausea or abdominal pain.
- Swelling due to fluid retention (oedema).
- Agitation or nervousness.
- Thought disturbance or paranoia.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Mania or psychosis.
- Abnormal coordination.
- Difficulty performing voluntary movements, resulting in jerky or involuntary movements or muscle twitches (dyskinesia).
- Abnormal muscle tension (dystonia).
- Increased rigidity or spasticity of muscles (hypertonia).
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.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.
Vigabatrin may decrease the blood level of phenytoin.
This medicine should not be taken in combination with any other medicines that can have side effects on the eyes or eyesight, for example chloroquine.
It is recommended that people who are taking any antiepileptic medicines should avoid taking the herbal remedy St John's wort (Hypericum perforatum). This is because St John's wort may affect the level of antiepileptic medicines in the blood and could increase the risk of seizures.
Other medicines containing the same active ingredient
There are currently no other medicines available in the UK that contain vigabatrin as the active ingredient.