How Seizure Medicines Work


Medicines can control seizures in about 7 out of 10 people. However, a person’s response to medicine may vary.

  • Research has shown that when people first start on seizure medicine, only 47% became seizure free with the first medicine. When a second drug was tried, another 14% of people became seizure free. When more than two drugs were tried the response to medicines decreased markedly. 
  • This study, along with other research, stresses the need for people to seek help for their seizures early. If medicines aren’t working, it’s important to see a doctor who specializes in epilepsy.
  • There are many different medicines for seizures and many of these can help - when they are given for the right type of seizures, at the right dose, and to the right person.

Seizure medicines don’t ‘fix’ the problems that cause seizures. Instead, they try to prevent or stop the seizures. Seizure medicines work in complex ways.

  • Many medicines act on brain cells to affect the way substances move in and out of the cells.
  • Others try to change the way substances called ‘neurotransmitters’ excite (e.g. stimulate) or inhibit (e.g. stop or slow down) the way information is sent from one cell and area of the brain to another.
  • By changing the way brain cells work or send messages, medicines can ideally stop the way seizure activity begins and spreads through the brain.
  • Scientists are constantly trying to find new ways that medicines could stop or control seizures. Some of the newer medicines work in a different way than the older medicines. It’s hoped that people who don’t respond to the older medicines may find a good response to a drug that works differently in the brain.

The goal of treatment with medicines should be – “No Seizures and No Side Effects”. In reality though, it’s hard for many people to get complete control.

  • Some people have too many medicine side effects.
  • Sometimes the side effects don’t bother people or are worth the benefits of not having seizures.
  • Other times, the side effects are very bothersome or cause other health problems.
  • In other people, seizure medicines may help, but don’t make a person seizure free. Whether or not this is ‘good enough’ will depend on the type of seizures, other neurological problems, the way the person responds to the medicine, or side effects, for example.
  • If the first drug helps some, but not enough, usually a second drug will be added. Ideally, a person can be kept on one drug but some people may need two or more medicines to get the best seizure control they can.  

How do I reach these goals?

While these goals cannot be achieved in everyone, improve your chances by following these steps:

  • Be open and honest with your doctor about your seizures and how they affect your life.
  • Be open and honest with your doctor about side effects and how they affect your health and daily life.
  • Follow instructions faithfully. Do not stop taking any seizure medicine or change the amount you take unless the doctor tells you to do that. If you often forget to take your medicine, be honest with the doctor or nurse about that, too.
  • Sometimes it’s hard to talk with your doctor or other health care professionals. You may not have time during visits or are not satisfied with your care. If this happens, talk to the doctor or health care professional about how you feel. Share your concerns and ask questions.
  • If you can’t talk openly with your team, or you aren’t working towards the same goals, it may be time to get a second opinion.

When you are trying a new medicine, consider these questions.

  • How does this medicine work and is it different than the seizure medicines that you have tried before?
  • How helpful has the drug been in research studies? What is the likelihood that your seizures will get better? For example, what is the chance of being seizure free? What is the chance of having your seizures cut in half or decrease by at least 50%?
  • Does the way the seizure medicine works mean that it may work better when given with some medicines than with others?
  • What are the side effects of the new medicine and what can you expect when it is added to your current medicines?
  • Does the new medicine interact with other medicines you may take for other conditions?
  • What is known about the use of the medicine during pregnancy or while breastfeeding?

Authored By:

Joseph I. Sirven MD / Patricia O. Shafer RN MN
Steven C. Schachter, MD

on Monday, July 29, 2013

Reviewed By:

Joseph I. Sirven MD / Patricia O. Shafer RN MN

on Wednesday, March 19, 2014


Epilepsy Centers

Epilepsy centers provide you with a team of specialists to help you diagnose your epilepsy and explore treatment options.


Epilepsy Medication

Find in-depth information on anti-seizure medications so you know what to ask your doctor.


Epilepsy and Seizures 24/7 Helpline

Call our Epilepsy and Seizures 24/7 Helpline and talk with an epilepsy information specialist or submit a question online.


Tools & Resources

Get information, tips, and more to help you manage your epilepsy.


Find an Epilepsy Specialist

Ready for help? Find an Epilepsy specialist who can help guide you through your epilepsy journey.