Seizure medication side effects: what to do about them?

  • March 27, 2026
  • 5
     
    min
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Have you recently started taking anti-seizure medication (ASM) and noticed medication side effects? Epilepsy medication side effects are very common - studies suggest that 20-40% of people on ASM’s experience at least one side effect.

If you have any concerns about seizure medication side effects, speak with your doctor. They can give you more advice depending on the ASM you take. The following information can give you an overview of some of the issues around ASM side effects.

What are anti-seizure medication side effects?

Medication side effects are any kind of additional - and usually unwanted - effects of a medicine. With ASMs, the medication may bring your seizures under control, but they could also cause unpleasant feelings and physical symptoms.

There are many types of ASMs. Each of them works in different ways - and they all have different possible side effects. To find out about the specific side effects of your ASM, speak with your doctor and read the leaflet that comes in the packet. 

How long do anti-seizure medication side effects last?

Sometimes, anti-seizure medication side effects pass away on their own in a few days or weeks. Your body may just need to adjust to the medication. Eventually you may start feeling like yourself again.

There are some side effects that can develop after you’ve been taking ASMs for a longer amount of time. These can include osteoporosis (reducing density of bones) - which may not be reversible. Other issues include sexual difficulties, weight gain or weight loss (these might be reversible). Monitoring these, and talking about them with your doctor, is important.

Serious anti-seizure medication side effects

Most medication side effects are simply unpleasant or irritating and may go away after a while (but talk to your doctor if you notice them).

However, certain epilepsy medication side effects could be serious. These can include the following (among others):

  • Agitation 
  • Aggression 
  • Psychosis
  • Changes in behaviour
  • Worsening of seizures
  • Suicidal behaviour

Also, if you notice that you have developed a rash somewhere on your body (usually soon after starting a new ASM), it could mean you have developed an allergic reaction. Contact your epilepsy specialist if you get a rash.

Special cases with ASM side effects

While it’s always important to monitor ASM side effects, there are some situations that may require a re-assessment of dosage and anti-seizure medication side effects:

  • Pregnancy and pregnancy planning: If you are planning to become pregnant, you should talk to your doctor as far in advance as possible. This is because some types of anti-seizure medication may affect the baby’s health, so your doctor may want to move you onto a different ASM. If you get pregnant unexpectedly, don’t stop taking your seizure medication. Contact your doctor immediately to work out a plan. 
  • Babies and young children: They may be unable to tell parents about any unpleasant feelings they are having. Talk with the child’s doctor about how to identify possible side effects, and talk to them about anything unusual that you notice.
  • People with learning difficulties: People with learning difficulties may also struggle with side effects of ASMs. Carers should talk to the doctor about how to identify possible side effects.

What can your doctor do about seizure medication side effects?

If you notice you're having anti-seizure medication side effects, your doctor might try a range of strategies:

  • Reducing dosage: Sometimes side effects happen because there might simply be too much of the ASM in your system - reducing the dosage may help.
  • Slowing dosage increase: Alternatively, when you first begin using ASMs, you normally increase dosage over time (titration). If you experience side effects, your doctor might slow down titration.
  • Trying a different ASM: It may also be helpful to simply try a different ASM. Newer generations of ASMs may have fewer side effects.

It can also be helpful to monitor your medication side effects so you can talk about them with your doctor.

Managing epilepsy medication side effects

Although seizure medication side effects can be very unpleasant, they may pass on their own as your body adjusts. Rather than stopping taking seizure medication if you get side effects, talk to your doctor about them. Working together, you can develop a plan to manage epilepsy medication side effects.

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