Topamax

How does it work?

Topamax tablets and sprinkle capsules contain the active ingredient topiramate, which is a medicine that is used to treat epilepsy.

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.

Topiramate works in three ways to prevent epileptic fits. Firstly, it enhances the activity of a neurotransmitter called GABA in the brain. Neurotransmitters are 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 calming agent. It keeps the nerve activity in the brain in balance. As topiramate enhances the action of GABA, it helps calm the nerve activity in the brain.

Topiramate also prevents sodium from entering the nerve cells when they begin to fire rapid and repetitive electrical signals. A build up of sodium in the nerve cells is necessary for the electrical signal to build up and be passed on. Topiramate therefore prevents the excessive electrical activity that causes fits.

Topiramate also decreases the ability of a neurotransmitter called glutamate to excite the nerve cells. It does this by blocking glutamate receptors.

All these actions calm the nerve cells and stabilise the electrical nerve activity in the brain. This helps prevent fits and maintain normal brain function.

Topiramate is used as an add-on treatment for adults and children over two years of age whose epilepsy has not been well controlled by other antiepileptic medicines. It can also be used as a single treatment for adults and children over six years of age who have newly diagnosed epilepsy.

Topiramate is also prescribed by specialists to prevent migraine headaches in adults, for example, for those who have three or more migraine attacks per month, or frequent migraines that significantly interfere with daily routine. It is not fully understood how topiramate works to prevent migraines. The medicine has to be taken continuously to prevent migraines. It is not intended for treating individual migraine attacks.

What is it used for?

Generalised tonic-clonic seizures

Partial seizures

Type of severe childhood epilepsy (Lennox-Gastaut syndrome)

Prevention of migraine in adults

Warning!

Topamax tablets should be swallowed whole, not broken. Topamax capsules can be swallowed whole, or can be opened and the contents sprinkled on a teaspoon of soft food, such as mashed banana, apple sauce, ice cream or yoghurt. If you do this, the food and medicine mixture should be swallowed immediately without chewing. It should not be kept for later use.

This medicine may cause drowsiness and problems with concentration. If affected do not drive or operate machinery. Drinking alcohol is likely to increase any drowsiness.

You should not stop taking this medicine suddenly unless your doctor tells you otherwise, as this may result in your seizures or migraines returning or getting worse. If it is decided that you should stop taking this medicine, it should be withdrawn gradually, according to the instructions given by your doctor.

It is important to drink plenty of water while taking this medicine, particularly in warm environments or when doing exercise. This is because topiramate has been reported to reduce sweating on rare occasions and this could cause flushing and raised body temperature. Drinking water helps keep the body cool. It is especially important to make sure children taking this medicine get enough fluid, as the majority of cases of raised temperature have been in children.

Topiramate may increase the risk of kidney stones, particularly if you have a personal or family history of kidney stones, or if you are taking other medicines that have this side effect. Drinking plenty of water also reduces the risk of developing kidney stones.

Topiramate has been associated with mood changes, depression and rarely suicidal thoughts or attempted suicide. You should discuss this with your doctor before starting treatment. If you have any mood changes, distressing thoughts, or feelings about suicide or harming yourself at any point while taking this medicine, then it is very important to talk to your doctor or go to a hospital immediately.

Rarely, this medicine may cause raised pressure in the eye (closed angle glaucoma). If you experience sudden eye pain or redness, or blurring of your vision, particularly in the first few weeks of treatment, then consult your doctor immediately. If you do have raised pressure in the eye, you will need to stop treatment with this medicine and start treatment to lower the pressure in your eye. Your doctor will explain more.

This medicine can cause loss of appetite and weight loss. You should be weighed regularly during treatment. If you are losing too much weight, or a child taking this medicine is not gaining enough weight, your doctor will ask you to increase the amount of food being eaten, or may prescribe dietary supplements.

If you are taking an oral contraceptive at the same time as this medicine you should tell your doctor if you experience any changes in your menstrual bleeding, because this may mean that your contraceptive is becoming less effective at preventing pregnancy.

Use with caution in

Decreased liver function

Decreased kidney function

Personal or family history of kidney stones

High levels of calcium in the urine (hypercalciuria)

History of depression or suicidal thoughts

Adolescents and young adults

Severe lung/breathing disorders

Life long inherited blood diseases which can cause a variety of symptoms, including mental health problems (porphyrias)

Not to be used in

Epilepsy in children under two years of age

Migraine in children under 16 years of age

Breastfeeding

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 one or 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 may pass into breast milk. It should not be used by breastfeeding mothers. Seek medical advice from your doctor.

Label warnings

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.

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