Neurological Associates


Antiepileptic Drugs (AEDs)

The most common approach to treating the epilepsies is to prescribe antiseizure drugs.  

More than 20 different antiseizure medications are available today, all with different benefits and side effects. 

Most seizures can be controlled with one drug (called monotherapy).  Deciding on  which drug to prescribe, and at what dosage, depends on many different factors, including

  • The type of seizure or epilepsy being treatment. Some drugs are more effective at controlling partial seizures, while others are more effective at treating generalized seizures. Some medications may be prescribed for specific types of epilepsy, such as ethosuximide (Zarontin®) for absence seizures, or rufinamide (Banzel®) for Lennox-Gastaut syndrome.
  • Previous response to treatment. Different medications may be attempted if other medications failed to provide sufficient seizure control.
  • The age and medical history of the person with epilepsy. Some antiepileptic medications may be avoided in school aged children or the elderly. Others may be avoided for people with other medical conditions that may alter how they metabolize the medication, such as liver disease
  • Likelihood of pregnancy. Some AEDs are safer for a developing fetus than others, and may be preferable for women who may become pregnant.

There are specific syndromes in which certain antiseizure medications should not be used because they may make the seizures worse.  For example, carbamazepine can worsen epilepsy in children diagnosed with Dravet syndrome.

It may take several months to determine the best drug and dosage.  If one treatment is unsuccessful, another may work better.

Seizure medications include:

Generic Brand Name (in the U.S.)
Carbamazepine Carbatrol®, Tegretol®
Clobazam Frisium®, Onfi®
Clonazepam Klonopin®
Diazepam Diastat®,  Valium®
Divalproex Sodium Depakote®, Depakote® ER
Eslicarbazepine Acetate Aptiom®
Ezogabine Potiga®
Felbamate Felbatol®
Gabapentin Neurontin®
Lacosimide Vimpat®
Lamotrigine Lamictal®
Levetiracetam Keppra®, Keppra XR®
Lorazepam Ativan®
Oxcarbazepine Oxtellar®, Oxtellar® XR, Trileptal®
Perampanel Fycompa®
Phenytoin Dilantin®, Phenytek®,
Pregabalin Lyrica®
Primidone Mysoline®
Rufinamide Banzel®
Tiagabine Hydrochloride Gabitril®
Topiramate Topamax®, Topamax XR®
Valproic Acid Depakene®
Vigabatrin Sabril®

Monotherapy vs. Combination

For many people with epilepsy, seizures can be controlled with just one drug at the optimal dosage (monotherapy).

Combining medications usually amplifies side effects such as fatigue and decreased appetite, so doctors usually prescribe monotherapy, or the use of just one drug, whenever possible. Combinations of drugs are sometimes prescribed if monotherapy fails to effectively control a patient’s seizures.

Dosage of Antiepileptic Drugs

When a person starts a new epilepsy drug, the dosage is adjusted to achieve safe and effective levels in the blood.

Blood tests may need to be performed to ensure that the amount of the drug being taken is resulting in an appropriate concentration in the blood. The "therapeutic blood level" is the concentration of medication in the blood that has the greatest likelihood of controlling seizures while minimizing side effects. If the blood level of the antiepileptic drug is too high, your doctor may lower the dosage or frequency of your medication. If the blood level is too low, your doctor may raise the dosage or frequency of your medication.

Different people react to AEDs in very different and sometimes unpredictable ways, so it may take time to find the right medication at the right dose to provide optimal control of seizures while minimizing side effects. A medication that has no effect or very bad side effects at one dose may work very well at another dose. Doctors will usually prescribe a low dose of the new medication initially and monitor blood levels of the drug to determine when the best possible dose has been reached.

The number of times a person needs to take medication each day is usually determined by the drug’s half-life, or the time it takes for half the drug dose to be metabolized or broken down into other substances in the body. Some drugs, such as phenytoin and phenobarbital, only need to be taken once a day, while others such as valproate must be taken two or three times a day.

Generic versions are available for many antiepileptic drugs. The chemicals in generic drugs are exactly the same as in the brand-name drugs, but they may be absorbed or processed differently in the body because of the way they are prepared. Therefore, patients should always check with their doctors before switching to a generic version of their medication.

Take your antiepileptic medication exactly as directed by your doctor. Do not take more or less of it, or take it more often than prescribed by your doctor. Talk to your doctor before you change or take any new medications.

Side Effects of Antiepileptic Drugs

Most side effects of antiepileptic drugs are relatively minor, such as fatigue, dizziness, or weight gain. However, severe and life-threatening side effects such as allergic reactions can occur. Epilepsy medication also may predispose people to developing depression or psychoses. People with epilepsy should consult a doctor immediately if they develop any kind of rash while on medication, or if they find themselves depressed or otherwise unable to think in a rational manner.

Other danger signs that should be discussed with a doctor immediately are extreme fatigue, staggering or other movement problems, and slurring of words. People with epilepsy should be aware that their epilepsy medication can interact with many other drugs in potentially harmful ways. For this reason, people with epilepsy should always tell doctors who treat them which medications they are taking. Women also should know that some antiepileptic drugs can interfere with the effectiveness of oral contraceptives, and they should discuss this possibility with their doctors.

Since people can become more sensitive to medications as they age, they may need to have their blood levels of medication checked occasionally to see if the dose needs to be adjusted. The effects of a particular medication also sometimes wear off over time, leading to an increase in seizures if the dose is not adjusted. People should know that some citrus fruit, in particular grapefruit juice, may interfere with breakdown of many drugs. This can cause too much of the drug to build up in their bodies, often worsening the side effects.

People taking epilepsy medication should be sure to check with their doctor if their medication does not appear to be working or if it causes unexpected side effects.

Discontinuing Antiepileptic Drugs

Some people with epilepsy may be advised to discontinue their antiseizure drugs after 2-3 years have passed without a seizure. Others may be advised to wait for 4 to 5 years. Discontinuing medication should always be done with supervision of a health care professional. It is very important to continue taking antiseizure medication for as long as it is prescribed. Discontinuing medication too early is one of the major reasons people who have been seizure-free start having new seizures and can lead to status epilepticus. Some evidence also suggests that uncontrolled seizures may trigger changes in the brain that will make it more difficult to treat the seizures in the future.

The chance that a person will eventually be able to discontinue medication varies depending on the person's age and his or her type of epilepsy. More than half of children who go into remission with medication can eventually stop their medication without having new seizures. One study showed that 68 percent of adults who had been seizure-free for 2 years before stopping medication were able to do so without having more seizures and 75 percent could successfully discontinue medication if they had been seizure-free for 3 years. However, the odds of successfully stopping medication are not as good for people with a family history of epilepsy, those who need multiple medications, those with focal seizures, and those who continue to have abnormal EEG results while on medication.

Reference: The National Institute of Neurological Disorders and Stroke (NINDS)

Last updated May 3, 2017