Determinants of medication withdrawal strategy in the epilepsy monitoring unit

Abstract

SUMMARY Background. Video-EEG (VEEG) monitoring is a vital diagnostic tool, but there are no guidelines for withdrawal of antiepileptic drugs (AEDs). Aim. The main objectives of this study were to understand the different withdrawal strategies used in the EMU, how strategies are chosen, and the efficacy and safety of different withdrawal strategies in producing seizures. Materials and methods. We retrospectively analyzed 95 consecutive patients and measured time to first seizure, incidence of status epilepticus, and need for rescue medications. Results. We found that AED withdrawal strategies can be divided into four categories based on level of aggressiveness. The main factors which impacted choice of strategy was number of AEDs on admission and frequency of pre-admission seizures. Abrupt cessation of medications was correlated with longer time to first seizure compared to other methods (hazard ratio (HR) 0.36, 95% confidence interval (CI) 0.20–0.65, p = 0.0007). Patients remaining on medications had shorter time to first seizure (HR 2.98, 95% CI 1.22–7.24, p = 0.016). Withdrawal technique was not correlated with need for rescue medications (OR 5.0, 95% CI 0.77–43, p = 0.20). No patients had status epilepticus in the study. Conclusions. Pre-admission seizure frequency and number of AEDs are the main factors which drive choice of withdrawal strategy on the epilepsy monitoring unit (EMU). Counterintuitively, least aggressive strategy is associated with highest risk of seizures. Results of this analysis suggest that disease factors, not choice of withdrawal strategy, determine seizure frequency on the EMU.