Anti-seizure medication

Also called anti-epileptic drugs or anticonvulsants

Key points about anti-seizure medication

  • Anti-seizure medicines are the main form of treatment for people with epilepsy.
  • Anti-seizure medicines work by stabilising the electrical activity of your brain.
  • Find out how to take them safely and about possible side effects.
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Anti-seizure medicines work by stabilising the electrical activity of your brain. Up to 70% (7 in 10) people with epilepsy could have their seizures completely controlled with anti-seizure medicines. Read more about epilepsy.

There are several different anti-seizure medicines available in New Zealand.

 Commonly prescribed anti-seizure medicines

Avoid valproate during pregnancy

If you are a woman of child-bearing age and could possibly get pregnant, you should avoid valproate, if possible. If you use it during pregnancy, there is a risk of harm to your unborn baby, as well as long-term developmental disorders once they are born. If valproate is the best choice for you despite this, it’s important you understand the risks. Talk to your doctor about this and ensuring you have effective contraception so you avoid unplanned pregnancy.  Read more about epilepsy and pregnancy and epilepsy and contraception

Other anti-seizure medicines include 
  • acetazolamide
  • clonazepam
  • ethosuximide 
  • gabapentin 
  • lacosamide
  • nitrazepam
  • oxcarbazepine 
  • phenytoin
  • phenobarbital
  • pregabalin
  • primidone
  • vigabatrin
  • diazepam
  • midazolam
  • stiripentol

Some anti-seizure medicines are more suitable for different seizure types than others. Read more about the different types of seizures. The following is a guide to the main anti-seizure medicines used in different seizure types:

Type of seizure Anti-seizure medicines options
Absence seizures sodium valproate, ethosuximide, lamotrigine
Myoclonic seizures sodium valproate, lamotrigine, clobazam,
levetiracetam, topiramate
Atonic seizures sodium valproate,  clobazam
Tonic seizures sodium valproate,  clobazam
Generalised tonic-clonic seizures sodium valproate, levetiracetam, clobazam, lamotrigine,
Focal seizures
  • focal aware
  • focal impaired awareness
  • focal to bilateral tonic-clonic seizure
carbamazepine, lamotrigine,  sodium valproate,
levetiracetam, clobazam, oxcarbazepine,
phenytoin, topiramate, lacosamide

All anti-seizure medicines can have side effects in some people but the majority of people do not get side effects. Some side effects may impact your lifestyle more than others. Some side effects may be life-threatening. Talk to your healthcare provider about possible side effects with your medication. 

  • Common side effects when starting anti-seizure medicines include tiredness, feeling sleepy, dizziness, dry mouth, feeling sick (nausea), diarrhoea (loose stools) and stomach upset. These usually go away as your body gets used to the medication. 
  • Life-threatening side effects that are possible with some anti-seizure medicines include severe skin reactions, problems with your liver and problems with your blood cells such as your white blood cells or platelets.
  • To help reduce your chance of side effects, your doctor may:
    • start you on a lower dose, then gradually increasing it; this allows your body to slowly get used to the medicine
    • ask you to have blood tests to make sure you are taking the right dose and check you don't have serious side effects. 

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(external link)

The decision when to start medication can be difficult. A first seizure may not mean that you will have a second seizure and a second seizure may not occur for years later. The decision to start medication should be made by thinking about the benefits and risks of starting, or not starting, the medicine. A common option is to wait and see after a first seizure. If you have a second seizure within a few months, more are likely, so it may be a good idea to think about starting medication.

Deciding on which anti-seizure medicine is best for you depends on many things such as:

Your health professional can discuss the best medication for you. It may take some time to find the anti-seizure medicine that works best for you. In most cases, only one anti-seizure medicine is needed to prevent seizures, but some people may need two or more medicines.

Assessing the benefits and risks

It is also important for you to think about the benefits and risks of taking, or not taking, anti-seizure medicines. This may depend on how your seizures affect you and how often they happen. The following table sets out what you might want to think about to help you decide whether to take anti-seizure medicines or not.

Benefits of taking anti-seizure medicines Risks of taking anti-seizure medicines

  • Reducing or stopping your seizures so that they don’t interfere with your day-to-day life. Up to 70% (7 in 10) people with epilepsy could have their seizures completely controlled with anti-seizure medicines
  • Reducing the chance of your seizures causing you to have accidents or injuries.
  • Reducing your worry that you will have a seizure.
  • Reducing the chance of getting status epilepticus which are seizures that continue without stopping, or a series of seizures that happen for 30 minutes without you recovering in between. This can happen with any seizure type.
  • Reducing the chance of SUDEP (Sudden Unexplained Death in Epilepsy Patients). Read more about SUDEP.
  • Having side effects from the medicine.
  • Needing to remember to take your medicine regularly. 

Anti-seizure medicines are usually available in tablets, capsules and liquids. If you find taking tablets difficult, ask your doctor to prescribe you something easier to swallow – some tablets are chewable or crushable.    

Epilepsy medicine is usually taken once or twice each day. Sometimes it is taken 3 times a day. It’s important to take it regularly, as prescribed by your doctor, because missing a dose can increase the risk of having a seizure. Read more about tips for remembering to take medicine.

Once you are prescribed epilepsy medicine, it’s a good idea to get advice about what to do if you ever forget to take it. The advice your doctor or pharmacist gives you will depend on which epilepsy medicine you are taking, and the dose.

Anti-seizure medicines do not cure epilepsy, but they can stop the seizures happening. For some people, having epilepsy is a lifelong condition and they will need to continue taking medication. If you have not had a seizure for 2 or more years, you may want to discuss with your doctor about the option of coming off treatment. This will depend on several things, including the possible impact of seizures returning.  

When coming off anti-seizure medicines, it is important that it is done slowly. Suddenly stopping treatment is dangerous. It can cause seizures to start again or happen more often and last longer than before. You can plan with your doctor how to come off the medication slowly and decide what to do if your seizures start again. If seizures do start again, taking the same anti-seizure medicines straightaway usually gives you the same control over your seizures as before. However, sometimes the anti-seizure medicine may not work as well as before.     

The following links provide further information about anti-seizure medication. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Medicines for epilepsy, mental health and pain can harm your unborn baby(external link) ACC, NZ 
Epilepsy(external link) Better Health Channel, Australia
New to epilepsy treatment(external link) Epilepsy Society, UK 
About epilepsy: the basics(external link) Epilepsy Foundation, US


  1. Prescribing issues associated with anticonvulsant medications for epilepsy(external link) BPAC, NZ, November 2009 
  2. Antiepileptic drugs(external link) NZ Formulary

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: 1] Associate Professor Lynette Sadleir, Paediatric Neurologist, University of Otago, Wellington 2] Angela Lambie, Pharmacist, Auckland

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