Lamictal (lamotrigine)

Main useActive ingredientManufacturer
Epilepsy LamotrigineGlaxoSmithKline

How does it work?

Lamictal tablets and dispersible tablets contain the active ingredient lamotrigine, which is a medicine used to treat epilepsy. (NB. Lamotrigine is also available without a brand name, ie as the generic medicine.) Lamotrigine works by stabilising electrical activity in the brain.


Lamotrigine prevents epileptic fits by preventing excessive electrical activity in the brain. It does this by preventing sodium from entering 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 to other nerve cells. As lamotrigine prevents this, it helps stabilise the electrical activity in the brain.

Preventing the build-up of the electrical signal also prevents the release of a neurotransmitter called glutamate from the nerve cells in the brain. Neurotransmitters are chemicals that are stored in nerve cells and are involved in transmitting messages between the nerve cells. Glutamate is a neurotransmitter that acts as a natural 'nerve-exciting' agent. It is released when electrical signals build up in nerve cells and subsequently excites more nerve cells. It is thought to play a key role in causing epileptic seizures. Reducing the release of glutamate from the nerve cells in the brain is another way in which lamotrigine helps stabilise the electrical activity in the brain and prevent epileptic fits.

In addition to its use for treating epilepsy, lamotrigine is used by specialists as a mood stabiliser for treating people with the psychiatric illness, bipolar affective disorder. Lamotrigine is used to help prevent episodes of depression in people who suffer mostly from this side of the illness. It is not fully understood how lamotrigine works in this illness, but is thought to be to do with the reduction of glutamate in the brain.

Lamictal tablets should be swallowed whole with a drink of water. Lamictal dispersible tablets may be chewed, dispersed in a small volume of water (at least enough to cover the whole tablet) or swallowed whole with a little water.

What is it used for?


  • Adverse skin reactions have been reported with lamotrigine. These reactions are usually mild and get better on their own, but can on rare occasions be more serious and potentially life-threatening. The risk is higher in children under 12 years of age and in people who are also taking the medicine valproate. When starting treatment with lamotrigine the dose is increased gradually to minimise the risk of developing a skin rash. For this reason it is very important to follow the instructions you are given with this medicine, and not to exceed the prescribed dose. If you or your child develop a rash, fever, facial swelling or swollen glands while taking this medicine you should consult your doctor immediately. If the doctor decides the reaction is related to this medicine you will need to stop taking it.
  • You should not stop taking this medicine suddenly unless your doctor tells you to, as this may result in your seizures returning or getting worse. If it is decided that you should stop taking this medicine, it should be withdrawn gradually, following the instructions given by your doctor. If for any reason you stop treatment for longer than five days and then restart, your doctor may want you to increase your dose gradually, as when you first started the medicine, to minimise the risk of getting a skin reaction.
  • This medicine may cause dizziness and double vision. As a result it could reduce your ability to drive or operate machinery safely. You should discuss this with your doctor. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.
  • There may be a small increased risk of suicidal thoughts and behaviour in people taking antiepileptic medicines such as lamotrigine for any indication. For this reason, it is very important to seek medical advice if you, or someone else taking this medicine, experience any changes in mood, 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.
  • The safety and efficacy of this medicine in children under two years of age has not been established by the manufacturer.

Use with caution in

Not to be used in

  • Known sensitivity or allergy to any ingredient.



Pregnancy and breastfeeding


  • 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 during pregnancy. 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.
  • If you decide to try for a baby while taking lamotrigine you should seek medical advice from your doctor as soon as possible. It may be recommended that you 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 lamotrigine during a pregnancy should, wherever possible, be prescribed lamotrigine on its own, in the lowest effective dose. Your doctor may need to adjust your lamotrigine dose from time to time, because changes to your body during pregnancy may affect the amount of lamotrigine in your blood and its effectiveness.
  • Lamotrigine passes into breast milk. Mothers who need to take lamotrigine should discuss the pros and cons of breastfeeding with their doctor. You should only breastfeed if the potential benefits of breastfeeding are considered to be greater than the risk of side effects from the medicine on the nursing infant. Seek medical advice from your doctor.

Label warnings

  • Do not stop taking this medication except on your doctor's advice.

Side effects


  • Skin rashes.
  • Headache.
  • Drowsiness.
  • Dizziness.
  • Pain in the joints or back pain.
  • Difficulty in sleeping (insomnia).
  • Visual disturbances, such as double vision or blurred vision.
  • Shaking, usually of the hands (tremor).
  • Confusion.
  • Agitation.
  • Irritability.
  • Aggression.
  • Hallucinations.
  • Disturbances in the numbers of blood cells in the blood.
  • Shaky movements and unsteady walk (ataxia).
  • Severe blistering skin reaction affecting the tissues of the eyes, mouth, throat and genitals (Stevens-Johnson Syndrome).
  • Disturbances of liver function.



How can this medicine affect other medicines?


Valproate (as sodium valproate, valproate semisodium or valproic acid) increases the blood level of lamotrigine. If you are taking a valproate medicine when you start treatment with lamotrigine, your starting dose of lamotrigine will be increased more gradually than normal. You should carefully follow the instructions given to you by your doctor or pharmacist.

Hormonal contraceptives (eg the pill) can reduce the amount of lamotrigine in the blood and make it less effective at controlling seizures. In addition, lamotrigine can make the pill less effective at preventing pregnancy. For this reason, women taking lamotrigine who need a contraceptive should preferably use a non-hormonal method such as condoms. When you start taking lamotrigine your doctor will review your contraception and advise on methods that are safe and effective for you to use. A hormonal contraceptive should only be used as the sole method of contraception if there is no other alternative. If the pill is chosen as your only method of contraception, you must tell your doctor if you experience changes in your menstrual pattern (eg bleeding between periods), as this may indicate that your pill is becoming less effective at preventing pregnancy. It is also important to tell your doctor if you plan to start or stop using hormonal contraceptives such as the pill while taking lamotrigine, as your lamotrigine dose may need re-adjusting.

The use of hormone replacement therapy (HRT) in combination with lamotrigine has not been studied, but it may interact in a similar way to hormonal contraceptives, by reducing the amount of lamotrigine in the blood and making it less effective at controlling seizures.

The following medicines may also reduce the blood level of lamotrigine:

  • carbamazepine
  • phenobarbital
  • phenytoin
  • primidone
  • rifampicin.

If you are taking any of these medicines with lamotrigine your doctor may need to increase your lamotrigine dose.

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.

There may be an increased chance of side effects such as headache, dizziness, blurred vision, double vision, sleepiness and nausea if carbamazepine or oxcarbazepine are taken with lamotrigine. If this occurs your doctor may need to reduce the dose of the carbamazepine or oxcarbazepine.

Other medicines containing the same active ingredient

Lamotrigine tablets and dispersible tablets are also available without a brand name, ie as the generic medicine.

Last updated 26.08.2008