Health Centres - Convulex
How does it work?
Convulex enteric-coated capsules contain the active ingredient valproic acid, which is a medicine that is used mainly to treat epilepsy. (NB. Valproic acid is another form of the antiepileptic medicine, sodium valproate. Both can be known simply as valproate.) Valproate 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, the brain becomes over-stimulated and normal function is disturbed. This results in fits or seizures.
Valproic acid works in the same way as sodium valproate; by preventing the excessive electrical activity in the brain. It is thought to achieve this by increasing the activity of a neurotransmitter called GABA in the brain.
Neurotransmitters are natural body chemicals that are stored in nerve cells and 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 nerve activity in the brain in balance.
Valproic acid is thought to increase the production and prevent the breakdown of GABA in the brain. This enhances the calming action of GABA in the brain, which stabilises the electrical nerve activity and helps prevent fits.
In addition to its licensed use for treating epilepsy, valproic acid is used off-licence by specialists as a mood stabiliser for treating people with the psychiatric illness, bipolar affective disorder. This use is not licensed, but valproate has been shown to be effective for controlling episodes of mania in this condition, and for helping prevent future episodes of ill health. It is not fully understood how valproic acid works as a mood stabiliser in bipolar disorder, but is thought to be to do with the increased activity of GABA in the brain.
What is it used for?
-
Epilepsy.
- Treatment of acute manic episodes in bipolar affective disorder (unlicensed use).
- As a mood stabiliser in bipolar affective disorder to help prevent episodes of mania or depression (unlicensed use).
Warning!
- You should not suddenly stop taking this medicine unless your doctor tells you otherwise, as suddenly stopping treatment is likely to make your symptoms return. If this medicine is stopped, it should normally be done gradually, under the supervision of your specialist.
- This medicine may cause drowsiness, especially if it is taken with other antiepileptic medicines, or with benzodiazepines such as lorazepam. This may affect your ability to drive or operate machinary.
- This medicine can cause some people to put on weight. Talk to your doctor about this before you start treatment so that you can discuss strategies, such as diet and exercise, for minimising any weight gain.
- This medicine may on rare occasions affect your liver, pancreas or blood cells. You should have blood tests to monitor your liver function, blood cells and blood clotting time before you start treatment. Your liver function should be monitored for the first six months of treatment, and your blood cell count should be checked before any surgery. Tell your doctor immediately if you, or a child taking this medicine, experience any of the following symptoms during treatment, particularly if they come on suddenly or occur in the first six months of taking the medicine: lack of appetite and energy, weakness, feeling generally unwell, drowsiness, nausea, vomiting, severe abdominal pain, swelling of ankles, yellowing of the skin or whites of the eyes (jaundice), or unusual bruising or bleeding.
- People with diabetes should be aware that valproic acid may cause false positive results in urine tests for ketones, ie the test may say that ketones are present in the urine even if they are not.
Use with caution in
- Young children
- Decreased kidney function
- History of liver disease
- Disorders of urea production in the liver (urea cycle disorders)
- Long-term inflammation of skin and some internal organs (systemic lupus erythematosus)
-
Diabetes.
Not to be used in
- Active liver disease
- Personal or family history of severely decreased liver function, particularly if due to a medicine
- Hereditary blood disorders called porphyrias.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
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 vital that women with epilepsy receive specialist advice before getting pregnant, so they are well informed of potential risks and benefits of continuing antiepileptic treatment. Pregnant women taking antiepileptic medicine have a higher risk of carrying a baby with developmental problems and malformations. However, if a woman with epilepsy stops treatment because she is pregnant, there is a risk of seizures that can harm both mother and baby.
- Women who decide to try for a baby while taking valproate should start taking folic acid 5mg daily as soon as contraception is stopped, as this may reduce the risk of neural tube defects such as spina bifida in the baby.
- Women who continue to take valproate during a pregnancy should, wherever possible, be prescribed valproate on its own, in the lowest effective dose, in doses that are split over the day, and if possible as a prolonged release brand. These measures can help minimise the risk to the baby. Specialist medical advice must be sought.
- Valproate passes into breast milk in small amounts, but there have been no reports of harmful effects from this on nursing infants. Seek further medical advice from your doctor.
Label warnings
- This medication is to be swallowed whole, not chewed.
- Do not stop taking this medication except on your doctor's advice.
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