- It's usual to take topiramate twice a day. You can take it with or without food.
- Common side effects of topiramate include feeling sleepy, dizziness, diarrhoea and feeling sick. These are usually mild and go away by themselves.
- If taking topiramate for epilepsy, it usually takes a couple of weeks for it to work. If taking topiramate to prevent migraines, it can take up to 3 months for it to work fully.
- Topiramate is also called by the brand name Topamax.
Topiramate can be taken by adults and children aged 2 years and over.
Topiramate is not suitable for some people.
Tell your doctor before starting the medicine if you:
- have ever had an allergic reaction to topiramate or any other medicines in the past
- have kidney problems, especially kidney stones
- have a blood disorder called acute porphyria
- have a history of blood metabolic acidosis, where the body produces too much acid or cannot remove it properly
- have eye problems, especially glaucoma
- have liver problems
- need to take high doses of vitamin C or calcium supplements
- are pregnant
Topiramate is a prescription medicine.
It's important to take it as instructed by your doctor.
How much will I take?
How much you take will depend on what you're using topiramate for.
It's usual to start topiramate at a low dose of 25mg to 50mg a day.
This will be increased over several weeks to the usual doses for:
- epilepsy - 100mg to 200mg a day, taken as 2 doses
- epilepsy (if you take another epilepsy medicine with topiramate) - 200mg to 400mg a day, taken as 2 doses
- migraines - 50mg to 100mg, taken as 2 doses
In children, the dose of topiramate will depend on the weight of your child.
Your doctor will be able to give the right dose to your child.
How to take it
It's usual to take topiramate twice a day. You can take topiramate at any time of day, but try to take your doses at the same time each day.
Try to space your doses evenly through the day. For example, first thing in the morning and in the evening.
Topiramate tablets can be taken with or without food. Swallow your tablets whole with a glass of water. Do not chew them.
Topiramate capsules can be swallowed whole or they can be opened and sprinkled on a teaspoon of soft food, like porridge or yoghurt.
What if I forget to take it?
If you forget to take a dose, take one as soon as you remember.
If it's less than 8 hours before the next dose is due, it's better to leave out the missed dose and take your next dose as normal.
Do not take 2 doses at the same time to make up for a forgotten dose.
If you forget doses often, it may help to set an alarm to remind you.
You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.
What if I take too much?
Ask your doctor for advice straight away. Taking too much topiramate by accident can lead to serious side effects.
Call your doctor straight away if you take too much topiramate and:
- feel dizzy or sleepy
- have difficulties talking
- have blurred vision
- have stomach pain
- feel confused or your normal behaviour changes
Like all medicines, topiramate can cause side effects, although not everyone gets them.
Common side effects
These common side effects may happen in more than 1 in 100 people. They're usually mild and go away by themselves.
Keep taking the medicine, but talk to your pharmacist or doctor if these side effects bother you or do not go away:
- feeling sick (nausea)
- feeling sleepy, dizzy or tired
- feeling depressed
- loss of appetite or weight loss
Serious side effects
Serious side effects are rare and happen in less than 1 in 10,000 people.
Tell your doctor straight away if you:
- get blurred vision, have difficulty seeing and eye pain – these can be signs of glaucoma; these symptoms usually occur during the first month of starting topiramate
- get pain in your back, belly or side, a burning sensation when you pee, cloudy or smelly pee – these are signs of kidney stones
- feel sleepy, lose your appetite, have an irregular heartbeat and faint – these can be signs of metabolic acidosis
- think your children are not sweating – some children taking topiramate may not sweat enough in hot weather, causing their body temperatures to rise
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to topiramate.
Call 999 or go to A&E if:
- you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
- you're wheezing
- you get tightness in the chest or throat
- you have trouble breathing or talking
- your mouth, face, lips, tongue or throat start swelling
You could be having a serious allergic reaction and may need immediate treatment in hospital.
These are not all the side effects of topiramate.
For a full list, see the leaflet inside your medicines packet.
You can report any suspected side effect to the UK safety scheme.
What to do about:
- feeling sick - stick to simple meals and do not eat rich or spicy food. It might help to take your topiramate after a meal or snack.
- feeling sleepy, dizzy or tired - do not drive or use tools or machinery. Try to avoid drinking alcohol, as this will make you feel more tired. If you feel dizzy, stop what you're doing and sit or lie down until you feel better. As your body gets used to topiramate, these side effects should wear off. If they do not after a few weeks or you feel dizzy all the time, speak to your doctor.
- diarrhoea - drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having strong-smelling pee. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.
- feeling depressed - if this continues, speak to your doctor.
- loss of appetite or weight loss - try to eat at usual meal times even if you do not feel hungry. If this becomes a problem, speak to your doctor or pharmacist.
There's no firm evidence that topiramate is harmful to an unborn baby.
But for safety your doctor will only advise you to take it in pregnancy if the benefits of the medicine outweigh the risks.
It's important for you and your baby to stay well during pregnancy.
If you become pregnant while taking topiramate, tell your doctor or nurse straight away.
Do not stop taking it without talking to your doctor first.
If you have epilepsy, it's very important that it's treated during pregnancy as fits (seizures) can harm you and your unborn baby.
If you're pregnant, or trying to get pregnant, and taking topiramate, you're recommended to take a higher dose of folic acid, a vitamin that helps your baby grow normally.
Your doctor might prescribe a high dose of 5mg a day for you to take while you're trying to get pregnant and during the first 12 weeks of pregnancy.
For more information about how topiramate can affect you and your baby during pregnancy, read the leaflet about the best use of medicines in pregnancy (BUMPS).
Topiramate and breastfeeding
If your doctor or health visitor says your baby is healthy, topiramate can be taken while you're breastfeeding.
Topiramate passes into breast milk, but it's unlikely to cause any side effects in your baby.
It's been linked with side effects in very few breastfed babies.
If you notice that your baby's not feeding as well as usual, or seems unusually sleepy, or you have any other concerns about them, talk to your pharmacist, health visitor or doctor as soon as possible.
Talk to your doctor if you're:
- trying to get pregnant
There are some medicines that may interfere with the effects of topiramate.
Tell your doctor if you're taking any of these medicines:
- medicines used to treat diabetes, such as metformin, glibenclamide and pioglitazone
- medicines used to treat depression or anxiety, such as venlafaxine and amitriptyline
- medicines for heart or blood pressure, such as diltiazem, hydrochlorothiazide and propranolol
- antipsychotic medicines, such as risperidone
- any other epilepsy medicines
Mixing topiramate with herbal remedies and supplements
Do not take St John's wort, the herbal remedy for depression, while you're being treated with topiramate.
This is because St John's wort may make topiramate less effective.
Tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.
How does it work?
Topiramate works by reducing the spread of seizure activity in the brain and restoring the normal balance of nerve activity.
For epilepsy - brain cells normally "talk" to each other using electrical signals and chemicals. Seizures can happen when the brain cells are not working properly or working faster than normal. Topiramate slows down these electrical signals to stop seizures.
For migraines - we do not fully understand how topiramate works. It's thought that topiramate calms overactive nerve cells in the brain that cause migraines.
How long does it take to work?
For epilepsy, it can take 1 to 2 weeks for topiramate to work properly.
For migraines, it can take 1 month for migraine attacks to be less frequent.
But it can take 2 to 3 months for topiramate to fully work.
How long will I take it for?
Once your condition is under control, you'll usually need to keep taking topiramate for many years.
Is it safe to take long term?
Yes, many people take topiramate safely for many months or years.
Are there similar medicines?
There are lots of other medicines that can be used for epilepsy and migraines, but they work in different ways.
They might have different side effects, or be taken more or less often.
If you have epilepsy, the choice will depend on the type of seizures that you have.
Your doctor will discuss the best medicine with you.
If you have migraines, there are other medicines that can be used to reduce the number of migraines you get.
These have different side effects and everyone responds differently to them.
How does topiramate compare with other medicines for epilepsy?
There are many different medicines for treating epilepsy.
It's not possible to say that one works better than the other.
It varies from person to person, and depends on the type of seizures and how often you have them.
Other epilepsy medicines include:
- sodium valproate
- valproic acid
To help to decide, your doctor will take into account your age and gender, the medicines you're already taking and any other health problems you may have.
It's usual to try to treat epilepsy using a single medicine.
If this medicine is not working well or you're getting side effects, your doctor will generally try you on a different one.
If a single medicine is not preventing your seizures, your doctor may recommend taking 2 or more epilepsy medicines at the same time.
If topiramate is giving you side effects or you're worried it's not working for you, ask your doctor or specialist to recommend a different medicine.
How does topiramate compare with other medicines for migraines?
There are different medicines available to prevent migraines.
- beta blockers, such as propranolol
- antidepressants, such as amitriptyline
- other epilepsy medicines, such as sodium valproate or gabapentin
It's not possible to say that one works better than the other.
The choice will normally depend on your age, gender, any other health conditions and how your other medicines have worked for you in the past.
Can I switch to a different medicine?
If you want to switch medicines, it's very important to do it exactly as your doctor tells you to.
Switching from topiramate to a different medicine will be different for each person.
If you want to switch, you'll usually start taking the new one at a low dose and slowly build up the dose while you're still taking topiramate.
Once you're taking the correct dose of the new medicine, you should be able to slowly reduce your dose of topiramate.
It can take several weeks or months until you have stopped taking topiramate completely.
Can I come off topiramate?
Do not stop taking topiramate suddenly unless your doctor tells you to.
You're unlikely to get any extra symptoms when you stop taking this medicine.
But if you're taking it to prevent migraines, your condition could get worse for a short time after stopping it.
If you're taking topiramate for epilepsy, it's possible that you'll get seizures once you stop taking it.
You can prevent these withdrawal seizures by reducing the dose of your topiramate gradually.
Will it affect my contraception?
Topiramate might stop these contraceptives working:
- combined hormonal contraceptives (the combined pill, patches, and vaginal ring) - look out for bleeding between periods, which might be a sign the pill is not working. Talk to your doctor if this happens. Your doctor may advise you to use a different type of contraceptive, or condoms as well as combined hormonal contraceptives.
- progestogen-only contraceptive pill and implants - your doctor may advise you to use a different type of contraceptive
- emergency contraception - tell your pharmacist or doctor that you take topiramate if you need emergency contraception. You may need an increased dose or to use the copper coil.
You can use the contraceptive injection or coil with topiramate.
Will it affect my fertility?
Topiramate does not affect male or female fertility.
Can I get epilepsy medicines for free?
If you have epilepsy, you're entitled to free prescriptions for all of your medicines, not just your epilepsy ones.
To claim your free prescriptions, you'll need a medical exemption certificate.
The application form for the medical exemption certificate is called FP92A.
You can get this from your doctor's surgery.
You'll need to fill in the form and your doctor will sign it and send it off.
Can I drink alcohol with it?
Yes, you can usually drink alcohol with topiramate.
But it may make you feel sleepy or tired, and alcohol and hangovers can bring on seizures in some people with epilepsy.
If you do drink, try not to have more than the recommended guidelines of up to 14 units of alcohol a week.
A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.
Are there foods and drinks I should avoid?
You can eat and drink normally while taking topiramate.
Can I drive or ride a bike?
You may feel sleepy, tired or dizzy when you first start taking topiramate.
This may also happen if your dose has increased.
If you're affected, do not drive or ride a bike or operate machinery until you feel more alert.
If you have epilepsy, you're not allowed to drive until you have had no seizures for 1 year.
If you change your epilepsy medicine, your doctor will tell you whether you need to stop driving and for how long.
Driving rules if you change or withdraw your medicine, Epilepsy Action
Epilepsy and driving information, GOV.UK