Medications for epilepsy

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Read about various anti-epileptic drug therapies available for your child.

Key points

  • Anti-epilepsy drugs (AEDs) treat the symptoms of epilepsy by reducing the frequency of seizures.
  • AEDs are most effective in children who began seizures before age 12, who have normal intelligence and who had fewer seizures before starting treatment.
  • The choice and dose of AED very much depends on your child's weight, age and symptoms and epilepsy history, but it can take some time to see if an AED is effective.
  • Always follow the medication instructions from your child's doctor.

The main mode of treatment for epilepsy is with medication called anti-epileptic drugs (AEDs). They are also referred to as anticonvulsant drugs.

Despite their name, AEDs do not "cure" epilepsy or seizures. They do not change the brain's underlying susceptibility to produce seizures. Most AEDs also do not change the child's EEG, except for a few specific conditions. They only treat the symptoms of epilepsy by reducing the frequency of seizures.

For most children, medication is all that is needed to control seizures, but although there is a good chance of success, AEDs do not always work. Studies indicate that AEDs are most effective in children who began having seizures when they were under 12 years old, who did not have neonatal seizures, who have normal intelligence and who had fewer seizures before beginning treatment.

Generally, medication is the first choice of treatment for epilepsy. Other treatments are usually tried only if medication fails to reduce the seizures or produces unacceptable side effects. Surgery for seizures may be recommended earlier if the cause of seizures is identified to be a brain lesion that is growing, such as a tumour.

When to use AEDs

AEDs are usually not given at the first "sign" of a seizure. Half the children who have one seizure never have another. However, a second seizure greatly increases the chance of having more seizures, so treatment is usually considered at this point. In many cases, AEDs are very effective, but it is impossible to tell for certain at the start of treatment whether this will be true for your child's needs and situation.

AEDs begin working once they reach the brain. The amount of medication that reaches the brain depends on the dose, the body's metabolism, interactions with other medicines and other factors.

AEDs can have different effects depending on the age of the patient. While similar medications may be given to adults and children, their usage and effects may be different. Children often absorb, metabolize and excrete medications more quickly than adults. In addition, children's physiology may change frequently because they are growing. The onset of puberty may create more changes. For all these reasons, AED dosages in children need to be carefully determined and continuously monitored.

Many AEDs are available on the market and new ones are in development. Which medication is used depends on your child. Medication treatment must be tailored specifically to suit each situation.

When using AEDs, it is preferable to use a single medication if possible. This is called monotherapy. This is simpler to administer, reduces the chance of side effects and avoids interactions between two or more medications.

For certain syndromes, other types of medications may be used, either alone or in combination with AEDs. More than one AED may be used for various reasons.

  • Sometimes one AED is not enough to control the seizures.
  • Sometimes the child may have several types of seizures and may need more than one medication to control them.
  • Sometimes the child has fewer side effects with two AEDs at moderate doses, rather than one AED at a high dose.

The use of more than one medication is called polytherapy. The interaction between two or more medications may increase or decrease the effectiveness of one or both, which may change the dosage needed. Their interaction may also cause more side effects.

Finding the right AED and dosage

Medication treatment must be tailored to suit each child because reactions to an AED can vary from person to person. Two children with the same type of seizure may require different medications, or different dosages of the same medication. Determining the right medication and right dosage is a complex process that can take weeks or months.

Your child's doctor will select an AED based on the child's age, the type of seizures they are having, and the potential side effects of the AED. Some AEDs are considered "first-line" medications, meaning that they are tried first because they are known to be useful for a particular syndrome or seizure type.

The next step is to determine the dosage. The amount of the AED in your child's body should be high enough to prevent seizures, but not so high that it causes excessive side effects. The dosage amount and schedule will be determined by your child's doctor, taking into account your child's age and weight, the symptoms they experience, and your observations during the first few weeks. For some AEDs, the doctor is also able to measure the drug level in your child's blood and tailor the dosage to the blood level.

In most cases it is best to begin with a low dose and gradually work up to the optimal dosage. This is sometimes called titration. This gradual introduction helps to minimize dose-related side effects.

Measuring AEDs in the blood

For some AEDs, there is an established "therapeutic range" for the blood level. This range has been established by clinical studies as the most effective blood level to control seizures and avoid side effects in most children. Your doctor may determine that your child is best treated with levels above or below this range.

Levels of AED in the blood can be measured with a simple blood test at most laboratories. Blood levels are affected by when the last dose was taken, so your doctor may ask you to have the blood test performed first thing in the morning, before taking the AED. This is called a "trough" drug level.

Changes in medication

Adhering to the medication treatment schedule is very important. Some children may be so sensitive to their medication that taking a dose of medication even one hour late can result in a seizure. Conversely, an increased level of the medication can show up as serious side effects. Your child's doctor can talk to you about how sensitive your child may be to changes in the time of their doses.

The optimal dose for your child may change over time, based on their weight and the underlying epilepsy. Changes in dose may be required to maintain a stable level of the AED.

Never discontinue an AED suddenly, as this can provoke seizures or status epilepticus.

Questions about anti-epileptic drugs for your child's doctor

Here are some questions you may want to ask when the doctor prescribes an anti-epileptic drug for your child.

Questions about giving the medication

  • What dose is my child taking?
  • Does the dose need to be titrated (gradually increased over time)?
  • What is the dosing schedule (once a day, twice a day, three times a day)?
  • Is it possible to take the medication only twice a day, or switch to another medication that only needs to be taken twice a day?
  • How rigid is the dosing schedule? If my child takes the medication half an hour early or an hour late, will that be a problem?
  • What should we do if my child misses a dose of this medication?
  • What should we do if my child accidentally takes too much of this medication?

Questions about what to expect

  • What are the chances that this medication will control my child's seizures?
  • What can I expect while my child is taking this medication?
  • How long will it take before we know if the medication is working?
  • How long will my child be taking this medication?

Questions about side effects and problems your child might experience

  • What kinds of physical side effects might there be?
  • What kinds of cognitive or learning side effects might there be?
  • What kinds of behavioural side effects might there be?
  • How long can we expect the side effects to last?
  • Does this medication have any serious side effects, for which we would need to contact a doctor or emergency services? How can we recognize those side effects?
  • Does this medication interfere with other medications?

Other questions

  • How often should my child come in for a follow-up appointment while taking this medication?
  • Will my child need blood tests for monitoring while taking this medication?
  • Is there anything I should tell my child's school about this medication?
Last updated: February 4th 2010