What are the potential risks of AED withdrawal?
The news that a child has epilepsy, or any chronic disease, is difficult. Even more difficult is the concept that there is no true “cure” for epilepsy. Medications are used to suppress seizures, but do not take away the epilepsy. These medications are taken daily, often multiple times per day. Anti-seizure medications (AEDs) can be associated with side effects, including sedation, lethargy, behavior changes, and dizziness- all of which negatively affect your child’s quality of life. Therefore, parents often question how long children need to take these medications.
Why do we use anti-seizure medications?
The first goal of AEDs is to control the seizures. Again, it must be stressed that AEDs do
not cure the underlying cause of the epilepsy- they only suppress seizures. Therefore, AEDs must be taken every day and not just when the child has experienced a seizure. Fortunately, the majority of children and adults, 70-90%, do respond to AEDs and are able to become seizure free. In order to reduce side effects, single medication is preferred over multiple medications, and the lowest possible dose of AEDs is used. The specific amount of each medication needed to control seizures varies from child to child. Sometimes seizure freedom is not achieved immediately because it can take time to determine the best dose for the child. Once seizures are controlled, medication is continued in order to maintain seizure freedom.
The medicine worked. Seizures have stopped! Now what?
After the child has maintained seizure freedom, the idea of gradually weaning medications is entertained. The period of seizure freedom necessary varies, although literature supports waiting until the child has been seizure free for at least two years. AEDs should never be stopped abruptly and should never be done without the guidance of a physician; this could lead to withdrawal seizures. Before weaning AEDs, parents, physicians, and the child (when able) should have a thorough discussion of the risks and benefits of AED withdrawal.
What are the potential risks of AED withdrawal?
Seizure recurrence
The greatest risk of AED withdrawal is seizure recurrence. This occurs in approximately 1/3 of seizure free children.
Who is more likely to have seizures after AED withdrawal?
It is difficult to predict who will have seizure recurrence, but there are some findings that suggest a child is more likely to have seizures. These include children with developmental delay, epilepsy onset prior to one year of age, epilepsy due to known brain malformations or underlying metabolic disease, prior history of having epilepsy that was difficult to control (intractable epilepsy), and prior history of having prolonged seizures (status epilepticus), and persistently abnormal EEG. These are all thought to be suggestive of greater degree of brain abnormality and more severe disease.
If my child has risk factors for seizure recurrence, can they still try to wean medications?
In the past, children who had these potential risk factors would not be given an opportunity to wean off of AEDs due to concern of seizure recurrence. Although these children are more likely to have seizure recurrence with AED withdrawal, these same children are also more likely to have seizure recurrence even if AEDs are not weaned. In other words, seizure recurrence in these children is just as likely to happen in those who continue AEDs as in those who wean AEDs. Therefore, the underlying cause of the child’s epilepsy is likely the cause of seizure recurrence, and not whether or not AEDs are weaned. In spite of this understanding, if the risk of seizure recurrence is felt to be quite high or if your child has a prior history of prolonged seizures requiring hospitalization, your child’s physician may not recommend AED withdrawal.
Refractory seizures
If seizures do occur after AED withdrawal, parents are often concerned that their child will not be able to become seizure free again. Fortunately, this is uncommon. The majority of children who have seizure recurrence with AED withdrawal will do so within the first two years and are then able to become seizure free once more when AEDs are restarted. However, approximately 5% of all seizure free children who withdraw AEDs do go on to have seizure recurrence and resultant intractable epilepsy. If the child does go on to develop refractory (intractable) epilepsy, parents are likely to attribute this to withdrawing AEDs.
Just as it is difficult to predict which child will have seizure recurrence, it is also difficult to predict which child will go on to have intractable epilepsy after medication withdrawal. The characteristics that occur more often in children with seizure recurrence, such as abnormal learning and more severe epilepsy, are also found more often in children who subsequently have refractory epilepsy.
Similar to the children who have seizure recurrence after AED withdrawal, seizure recurrence followed by intractability occurs just as often in those who do not withdraw medications as in those who do. This suggests that children who have seizure recurrence and those who go on to have intractable epilepsy are likely to do so because they have more severe disease and not because their anti-seizure medications were weaned. Therefore, intractable epilepsy after prolonged seizure freedom should not be attributed to AED withdrawal.
Should we wean AEDs?
There is no “correct” answer to this question. We know that the majority of children are able to be seizure free when treated with AEDs. Those who are seizure free for several years are often considered for withdrawal of medications. This can be both exciting and frightening for parents and children. Seizure recurrence can happen during AED withdrawal, and so children must be watched very closely. However, in children with more severe disease, this recurrence is just as likely to happen if AEDs are not weaned.
If seizures do come back after AED withdrawal, the majority of children are able to once again become seizure free when AEDs are restarted. A minority of children do go on to become refractory to medications. This is more likely to happen in those with more severe disease, and the risk of intractable epilepsy after prolonged seizure freedom is equally likely to occur whether or not medication is weaned. Therefore, all children who are able to become seizure free could potentially be considered for medication withdrawal under the guidance of an epilepsy doctor.
