Sounds like 'toe-pye-rah-mate'

Topiramate is used to treat epilepsy and to prevent migraine headaches. Find out how to take it safely and possible side effects.

What is topiramate?

Topiramate is used to treat epilepsy by preventing seizures and to help prevent migraine headaches. It reduces how often you get migraines but it will not treat a migraine once it has started. Topiramate works by reducing bursts of electrical activity in your brain and restoring the normal balance of nerve activity.

In Aotearoa New Zealand, topiramate is available as different brands (Topamax, Arrow-Topiramate, Topiramate Actavis).
It's important to keep to the same brand, especially when it is used for epilepsy. Avoid switching brands.


In Aotearoa New Zealand topiramate is available as tablets (25 mg, 50 mg, 100 mg and 200 mg) and sprinkle capsules (15 mg and 25 mg).

  • The dose of topiramate will be different for different people.
  • Your doctor will start you on a low dose and increase it slowly over a few weeks to reduce side effects such as drowsiness.
  • Topiramate is usually taken twice a day but sometimes when starting topiramate it is taken once a day for a week or more. 
  • Always take your topiramate exactly as your doctor has told you. The pharmacy label will tell you how much to take, how often to take it and any special instructions.

How to take topiramate

  • Timing: You can take topiramate with or after food. Take topiramate at the same times each day.
    • If you are taking it twice a day, take your doses in the morning and night.
    • If you are taking it once a day, then it's best taken at bedtime.
  • Swallow your tablets or capsules whole with a full glass of water, milk or juice. Don't chew them. If swallowing the capsules is a problem, you can open the capsules and carefully sprinkle the beads onto a small amount of soft food such as a teaspoon of porridge, yoghurt or custard. Swallow all of the food straight away. Don't chew the beads.
  • Missed dose: If you forget to take your dose, take it as soon as you remember if it is within 4 hours of when your dose was due. But if more than 4 hours have passed since the dose was due, just take the next dose at the right time. Don't take double the dose.
  • Keep taking topiramate every day. It may take a few weeks before you notice the full benefits of topiramate. Don't stop taking topiramate suddenly; talk to your healthcare provider before stopping because it can cause seizures if you stop taking it suddenly.

Things to consider before starting topiramate

Sex and pregnancy

Taking anti-seizure medicines while you are pregnant can potentially harm your unborn baby. If you are a sexually active female and are taking topiramate, you should use 2 effective means of contraception (such as an IUD and condoms) to avoid unplanned pregnancy. When you are taking topiramate it is extremely important to plan a pregnancy. You need to see your doctor 6 to 12 months before you would like to become pregnant so that you can reduce any risks to your baby. 

  • All anti-seizure medicines in pregnancy have the potential to harm an unborn child but the risks are higher with some medicines, including topiramate, especially early in your pregnancy and at higher doses. If you have epilepsy, having seizures while you are pregnant can also harm your unborn baby, so it is important to keep taking an anti-seizure medication.
  • Talk with your doctor to agree on a plan about how to manage your medicines and your dose. 
  • If you are pregnant or think you might be pregnant, keep taking your medicine at the right dose, and contact your doctor, tell them you think you are pregnant and get an urgent appointment to see them.

Read more about how medicines for epilepsy, mental health and pain can harm your unborn baby. 

Things to consider while you are taking topiramate 

Drink plenty of water 

Make sure you drink plenty of water to keep well hydrated while you are taking topiramate. It's important because topiramate can increase your body temperature and reduce sweating – especially during hot weather and when you exercise. This can put you at risk of getting dehydrated and can cause kidney stones. Tell your doctor immediately or ring Healthline 0800 611 116 if you get sudden pain in the stomach (tummy) area, difficulty passing urine (pee) or blood in your urine.

Taking other medicines

Topiramate can interact with some other medicines and herbal supplements, so check with your doctor or pharmacist before starting topiramate and before starting any new medicines or products.

What are the side effects of topiramate?

Like all medicines, topiramate can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Problems with your eyesight

Topiramate can cause increased pressure in your eye. This can affect your eyesight and cause symptoms such as blurred vision, eye pain, nausea (feeling sick) and vomiting (being sick), and headache. This can happen within one month of starting treatment. If you have any of these symptoms, contact your doctor immediately. 

Other possible side effects

Side effects What should I do?
  • Feeling sleepy, drowsy or tired
  • Feeling dizzy
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Limit or avoid alcohol.
  • Tell your doctor if troublesome.
  • Runny poo (diarrhoea) or constipation
  • Tell your doctor if these bother you.
  • Stuffy, runny nose and sore throat
  • Dry mouth or changes in taste 
  • Tingling in the arms and legs
  • This usually wears off after a short time.
  • Tell your doctor if these bother you.
  • Changes in moods
  • Having low mood, feeling depressed, or feelings of hurting yourself.
  • Tell your doctor immediately or ring Healthline 0800 611 116. 
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.

Learn more

Topamax Medsafe Consumer Information Sheets, NZ 
Topiramate for children New Zealand Formulary for Children, NZ


  1. Avoid switching brands of topiramate Medsafe 2020
  2. Prescribing issues associated with anticonvulsant medications for epilepsy BPAC, November 2009
  3. Topiramate – titrate and hydrate SafeRx,November 2016
  4. Topiramate New Zealand Formulary
  5. Topamax New Zealand data sheet  
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 30 Nov 2022