Why are antiepileptic drugs continued after successful epilepsy surgery in adults?

Studies have demonstrated that a substantial number of patients continue treatment with antiepileptic drugs (AEDs) for many years after epilepsy surgery despite seizure freedom. In this study, we aimed to investigate why AED treatment is maintained in patients three and seven years after successful epilepsy surgery. To our knowledge, an analysis of this specific subgroup of completely seizure-free patients has not been done before.

Danish patients with medically refractory epilepsy and histopathologically proven hippocampal sclerosis operated between 1995 and 2014 who were reported seizure-free at one-year postsurgery were contacted by telephone in 2017 and retrospectively asked about the reasons to continue or taper AED at three and seven years after the operation.

Fifty patients were completely seizure-free three years after the operation. Of those, 31 (62%) were still taking AEDs at three years, thereof 10 (20%) in the same dose and number and half of those on their own wish. At seven years, nine patients were still taking AEDs, two in unchanged number and dose, both on their own wish. Fear of relapse was the most common reason not to withdraw medication. Presurgery seizure frequency for patients taking AEDs at three and seven years was not higher than for those who had discontinued taking AEDs.

A large portion of completely seizure-free patients still take AEDs even seven years after epilepsy surgery. This seems to be largely due to the patients' own wishes and fear of relapse, and unrelated to presurgery seizure frequency. Our results could aid in counseling patients on the decision to withdraw AEDs after successful epilepsy surgery.