Most patients with epilepsy become seizure-free during treatment with antiseizure medications (ASM) and current guidelines by the American Academy of Neurology (AAN) support ASM discontinuation in some individuals to reduce the side effect burden and improve quality of life (Gloss et al. Neurology 2021;97:1072-1081).

Online calculators enable clinicians to estimate the seizure risk after ASM withdrawal (http://epilepsypredictiontools.info/aedwithdrawal). However, such tools do not calculate the absolute seizure risk, i.e. the risk with ASM discontinuation vs. continuation.

A new database analysis has examined the seizure risk with ASM continuation and discontinuation in 1626 patients (Terman et al. Epilepsia Open 2024;9:333-344). The databases used were from the U.K. Medical Research Council study on drug withdrawal (Medical Research Council. Lancet 1991;337:1175-1180); the Akershus study (Lossius et al. Epilepsia 2008;49:455-463); and a recent retrospective chart review (Terman et al. Epilepsia Open 2023;8:371-385.).

The one-year seizure risk was 32% for patients who discontinued ASM compared to 13% for those who continued on treatment. The two-year seizure risk was 43% with ASM discontinuation versus 21% with drug continuation. The absolute seizure risk with ASM withdrawal was calculated as 19% and 21% at one and two years, respectively. No patient factors were identified that modified the seizure risk associated with ASM discontinuation.

The authors acknowledged that an “acceptable” seizure risk has not been determined and patients and clinicians will have different risk tolerances. A recent survey of AAN members reported that a median post-discontinuation risk of 15% for convulsive seizures and a 24% risk for nonconvulsive seizures would be acceptable for adult patients (Ternan et al. Neurol Clin Pract 2023;13:e200109). This suggests that a majority of patients in the present analysis would be candidates for ASM withdrawal.