Sounds like 'toe-PEER-uh-mate'

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

Type of medicine Also called
  • Belongs to a group of medicines known as anti-seizure medicines (to prevent seizures) but it also has other uses
  • Topamax®
  • Arrow-Topiramate®
  • Topiramate Actavis®

What is topiramate?

Topiramate is used to treat epilepsy by preventing seizures and helps to prevent migraine headaches. It reduces how often you get migraines but it will not treat a migraine once it has started. Topiramate works by blocking certain kinds of nerve activity.

In New Zealand, topiramate is available as different brands (TopamaxArrow-TopiramateTopiramate Actavis).
It is important to keep to the same brand, especially when it is used for epilepsy. Avoid switching brands.


In 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.
  • Topiramate is usually taken two times 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 two times 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 topiramate tablets or capsules whole with a full glass of water, milk or juice. Do not 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. Do not 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. Do not take double the dose.
  • Keep taking topiramate every day. It may take a few weeks before you notice the full benefits of topiramate. Do not stop taking topiramate suddenly; speak to your doctor or nurse before stopping because it can cause seizures if you stop taking it suddenly.

Precautions before starting topiramate

  • Are you pregnant or trying for a baby?
  • Are you breastfeeding?
  • Do you have any problems with the way your kidneys or liver work?

If so, it’s important that you tell your doctor before you start topiramate. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Special instructions

Drink plenty of water when taking topiramate

It is important to drink plenty of water while you are taking topiramate because it can cause an increase in your body temperature and reduced sweating, especially during hot weather and exercise. This can put you at risk of getting dehydrated and can cause kidney stones especially if you are not drinking enough water. Make sure you drink plenty of water to keep well hydrated while you are taking topiramate. 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.

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.
  • Stuffy, runny nose and sore throat
  • Tingling in the arms and legs
  • This usually wears off after a short time.
  • Tell your doctor if troublesome.
  • 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


Topiramate interacts with other medicines, including steroids and medicines that can make you dehydrated, and herbal supplements, so check with your doctor or pharmacist if you are taking topiramate. Topiramate can affect birth control pills 'the pill'. Talk to your doctor about the best types of contraception for you.  

Learn more

Medsafe Consumer Information Sheets Topamax
For children: topiramate New Zealand Formulary for Children


  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  

Useful resources for healthcare professionals

Topiramate NZ Formulary
Control of the epilepsies NZ Formulary
Helping patients with epilepsy adhere to their medicines BPAC, NZ, 2017
Topiramate – titrate and hydrate SafeRx, NZ, 2016

Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 21 Sep 2020