How it works
What does lamotrigine do?
Lamotrigine is a type of medicine called a ‘mood stabiliser’ as it can reduce feelings of excitability and over-activity and reduce mood swings. It tends to work better on the low mood (depression) part of bipolar disorder.
It is also taken by some people who have epilepsy, as it increases the effects of the calming transmitter GABA, leading to a reduction in seizures. This is a very separate use but will be covered in any patient leaflets.
How long will lamotrigine take to start working?
You may start off at a low dose and gradually increase it every few days or weeks until you and your doctor find the dose that is right for you. It may take up to six weeks to do this, by which time you should be a on a stable, long-term dose and have seen some helpful results from the medication.
It is important not to hurry the dosing timetable as doing so can increase your chances of getting a serious skin reaction.
How long will I need to take lamotrigine for?
You and your doctor should talk about how long you need to take lamotrigine before you begin treatment with this medication.
If you take lamotrigine for bipolar disorder you will probably take it for at least six months (any shorter and your old symptoms can come back). If it works for you, you may take it for much longer than that.
Your doctor needs to know if...
You need to talk to your doctor or pharmacist before starting treatment with lamotrigine if any of the following apply to you:
- you have kidney problems
- you develop rashes after taking lamotrigine or any other medicines for bipolar disorder or depression
- you have or develop a blood condition called HLH. It produces symptoms like fever, headache, feeling or being sick, stiff neck or your eyes being sensitive to bright light. It is also a very rare side effect of taking lamotrigine
Lamotrigine tablets have lactose in them which may not suit people who have a problem drinking milk or eating certain sugars. Talk to your doctor or pharmacist about this if you think it could be a problem for you.
You should only take lamotrigine as agreed with your doctor
Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.
You may have to take lamotrigine once or twice a day.
It doesn’t matter what time you take it each day – choose a time that you can always remember. This could be at mealtimes, or when you brush your teeth. You can take it before or after food.
If you are taking the tablets that you swallow whole, wash them down with a glass of water. Do not try and chew them – they will taste unpleasant.
If you are taking the orodispersible tablets (melts), get a glass of cold water and mix the tablet(s) in at least enough water to cover them. You can stir the drink to help them break up. 'Dispersible' doesn’t mean you will get a totally clear solution - it will look a little cloudy. Drink it all, and then add more water to the glass and drink that in order to make sure you get all the medicine in the tablet.
You can also chew the dispersible tablets, but it may help to rinse them down with some cold water.
You can still swallow the dispersible tablets whole with water if you prefer.
What if I miss a dose?
If you remember later during the day, take it as soon as possible. If you forget to take it by the time of the next dose, just start again with the next dose.
Do not take a double dose.
What will happen if I forget to take my lamotrigine?
If you forget to take your tablets for a few days, you may start getting your old symptoms of low mood back.
Stopping the use of lamotrigine
Although you may not be taking your lamotrigine for seizures (fits), if you stop the medication suddenly, there is a chance you may have a seizure. This is because after taking lamotrigine for some time, your body will have got used to having an anticonvulsant (anti-seizure) medicine on board. Suddenly stopping the use of lamotrigine may therefore cause a seizure. But don't worry - this doesn't mean you are suddenly epileptic.
If you have stopped taking lamotrigine, you need to speak to your doctor so that you can safely start it again and build back up to your dose. It is best to be honest; they will help you get back on track.
If you are thinking of stopping treatment with lamotrigine, talk to your doctor before doing this.
The information on this page was reviewed by the College of Mental Health Pharmacy in March 2020.