PHILADELPHIA — Most epilepsy patients whose seizures are completely controlled by antiepileptic drugs can eventually attempt withdrawal from treatment with a low risk of complications, Dr. Peter Camfield said at the annual meeting of the American Epilepsy Society.
The major nightmare of stopping antiepileptic therapy—that after successful drug treatment is stopped seizures will recur and will no longer be controllable by medications—occurs infrequently, and so attempting to take patients off of their drugs is a reasonable option for most epilepsy patients, said Dr. Camfield, a pediatric neurologist and head of the pediatrics division at Dalhousie University in Halifax, N.S.
In fact, “most children deserve a chance to come off of their AEDs [antiepileptic drugs] after being seizure free for 1–2 years,” he said. About 70% of children with epilepsy who are treated with AEDs become seizure free long enough to become candidates for discontinuation.
He cited data from the Nova Scotia follow-up study, which included 692 children with epilepsy; 389 patients were seizure free after treatment for at least 2 years and so were eligible to stop treatment. From this group, 280 patients elected to do so. Among those who stopped, 81 (29%) had a recurrence of seizures; the remaining 71% of patients remained seizure free without treatment during long-term follow-up.
Of the 81 children who had a recurrence, 78 (96%) were controlled again by restarting AED treatment. Only three patients were intractable to restarted treatment, less than 1% of the 389 who were eligible to try discontinuation, Dr. Camfield said.
A much lower percentage of adults are willing to stop their AEDs, and so the available data on adults are more limited. A literature review published in 2005 indicated that if seizures recur after treatment is stopped, about 80% of adult patients can quickly have their seizures controlled again by restarting treatment. The percentage of adults with seizures that are refractory to restarted treatment is low, but the rate may be higher than it is in children. It's reasonable to consider stopping AED treatment in adults who have been seizure free for about 4 years, Dr. Camfield said.
Stopping a successful AED regimen is a decision that patients—or their families—need to make individually, using the information that's available. Stopping treatment has the advantages of avoiding AED adverse effects and giving patients a sense that they are cured. Disadvantages include interrupting successful management; risking an unexpected recurrence that could have serious consequences, such as a seizure when driving, and concern about the rare case in which restarting treatment is not successful. Patients should also understand that even if they continue a successful regimen, there is no guarantee that they will remain seizure free in the future.
Childhood epilepsy syndromes can be classified by how often they remit. About 15% of patients always remit: those with benign rolandic seizures, benign familial infantile seizures, and early-onset, benign occipital epilepsy.
About 75% of children with epilepsy—a group that includes 17 different syndromes—will sometimes remit. Among these are typical childhood absence epilepsy, with about a 65% remission rate; cryptogenic partial epilepsy, with a 67% remission rate; and symptomatic partial seizures, with about a 50% remission rate.
About 10% of children with epilepsy never remit, including patients with juvenile myoclonic epilepsy, reading epilepsy, myoclonic absence epilepsy, and early myoclonic encephalopathy.
Although Dr. Camfield recommended that seizure-free patients wait 2 years (for children) to 4 years (for adults) before attempting to stop their treatment, results from observational studies suggest that children have about the same recurrence risk following drug discontinuation regardless of whether it occurs after 1, 2, 3, 4, or 5 years of seizure-free treatment. The data suggest that “AED treatment has nothing to do with remission of epilepsy,” he said.
In a Dalhousie University study, the significant predictors for the risk of recurrence in children following treatment withdrawal were female gender, an abnormal neurologic examination, epilepsy onset before the age of 10 years, and having a history of focal seizures (which was the strongest risk factor). The risk of recurrence was even higher in patients who had two or more of these risk factors.