Withdrawing antiepileptic medication after temporal lobe epilepsy surgery may increase the risk of breakthrough seizures in the short term but does not alter long-term remission rates, a retrospective, observational cohort study found.
Two years after surgery, 69% of patients whose medication was discontinued at 1 year were completely seizure free, compared with 72% of those whose medication was reduced at 1 year and 79% of those whose medication was unchanged, Dr. Ruta Yardi of the Cleveland Clinic and her colleagues reported in Annals of Clinical and Translational Neurology (Ann. Clin. Transl. Neurol. 2014;1:115-23 [doi:10.1002/acn3.35]).
The authors said that there is long-standing debate on how to manage antiepilepsy medication after surgery, with concerns about breakthrough seizures being countered by patient desire to cease medication, concerns about polytherapy toxicity, and the rising cost of medication. There is little, however, by way of guidance on postoperative antiepileptic medication management.
Dr. Ruta Yardi
"Our findings suggest though that postoperative AED [antiepileptic drug] management in this [temporal lobe epilepsy] cohort may reflect a compromise between needing to relieve patients from significant medication-related side effects and confidence about surgical success," Dr. Yardi and her associates wrote.
The researchers reviewed 609 patients (86% adults) who underwent temporal lobe epilepsy surgery during 1995-2011 and who had previously failed at least two antiepileptic drugs. Data on the exact dates of medication regimen change were available for 311 patients, including 253 who reduced their medication and 127 who stopped it entirely.
The study showed that long-term remission rates were similar in both the discontinuation groups (82% remission when medications were withdrawn after 1 year and 90% for medications withdrawn after 2 years) and the "unchanged" groups.
Patients who experienced seizures while their antiepileptic medication was being reduced, however, were less likely to achieve remission (50% remission rate) than were those who experienced breakthrough seizures after complete discontinuation of their medication (70%; P = .0001). Of the patients who experienced breakthrough seizures while their antiepileptic medications were being reduced, only 65% achieved 2-year remission.
"Patients with brain tumors (and thus an easily ascertainable complete removal of the epileptic focus) were at least twice as likely as those with any other epilepsy pathology to have their AEDs completely discontinued after surgery, while those with spikes on postoperative EEG (and thus an easily ascertainable presence of an epileptic focus) were almost twice as likely to continue their AEDs unchanged," the investigators wrote.
Among the 311 patients for whom data on medication change were available, the mean interval from surgery to starting withdrawal of medication was 1.34 years. This interval was longer in patients who had more than 20 preoperative seizures per month but tended to be shorter in children.
The mean interval from surgery to the latest change in medication was 1.64 years, and again, this interval was shorter in children (0.95 years vs. 1.76 years in adults, P = .002).
The authors declared having no conflicts of interest.