Postponing the morning dose of AEDs: effect on the epileptiform EEG activity

Background The effects of postponing the morning dose of antiepileptic drugs (AEDs) before undergoing an electroencephalogram (EEG) on the likelihood of recording interictal epileptiform activity (IEA) in patients with epilepsy are unclear. Methods This was a prospective study on patients undergoing video-EEG monitoring. The 3-h recordings used for evaluation started at 08:00 am. Each subject received the usual AED dosage at 08:00 am on the first full day of recording but not until 11:00 am on the following day. IEA (spikes, sharp waves, and spike and wave complexes) was counted at 1-h intervals on each day and compared. Each subject served as his/her own control. The measureable serum drug levels were obtained at 10:00 am on both days. Results Fifty patients (age 32 +/- 11.7 years, 22 women) were enrolled. Forty-seven had focal epilepsy, and three had generalized epilepsy. Six were on monotherapy, and 44 were on polytherapy. The number of IEAs w/wo medication was similar throughout each hour. Twenty-five patients had IEA on the 1st day, and 28 had IEA on the 2nd day. Twenty-one had IEA on both days, while 18 had none on either day. Seven of the 25 without IEA on the 1st day had IEA on the 2nd day, and 4 of the 25 with IEA had no IEA on the 2nd day. Age, gender, epilepsy type, disease duration, seizure frequency, and AED type did not influence IEA. Conclusions Delaying the morning dose of AEDs prior to an EEG tracing was not associated with increased IEA in patients with epilepsy.