Abstracts

With the exception of pregabalin, all of the second generation antiepilepsy drugs (AEDs) have been available for over 6 years. Many reports on retention and seizure response are done on an individual basis for the different AEDs from different institutions / authors . This makes comparison of the different AEDs difficult, as variation in reporting styles, differences in use of the drugs, and differences in methods can vary significantly from one center to another. It is also unlikely that a large study doing a direct side-to-side comparison of all the newer AEDs will be performed. We present the overall results of use of the newer AEDs from the same institution by the same authors., All patients treated at Penn State, Milton S. Hershey Medical Center were included. Charts of patients treated from January 1st, 1993 - June 30th, 2005 were reviewed from the time of the first exposure to each drug until the final visit for each patient. Patients treated less than 6 months for any of the drugs (aside from discontinuation) were excluded. The following drugs were investigated: gabapentin (GPN), lamotrigine (LTG), topiramate (TPM), oxcarbazepine (OXC), levetiracetam (LEV), and zonisamide (ZNS). Many patients were exposed to several of the newer AEDs and therefore data from each drug is expressed as patient exposures, rather than patients., During the study, there were a total of 1262 patient exposures to the second generation AEDs. Breakdown is as follows: GPN-96 patients, LTG-494 patients, TPM-232 patients, OXC-146 patients, LEV-294 patients, and ZNS-133 patients. Seizure-freedom was most likely to occur with LTG, TPM, or LEV, and least likely with GPN; ranging from 5% to 32%. Response varied in part depending on seizure type and how early in the treatment regimen patients were exposed to each drug. Despite many patients not becoming seizure-free, the majority chose to remain on the newer agents. Retention rates by the end of the study varied from 27% to 84% with 27% of patients remaining on GPB, 84.4% remaining on LTG, 84.1% remaining on TPM, 61.6% remaining on OXC, 66.3% on LEV, and 84.2% on ZNS. This suggests better tolerance with the newer AEDs, although this could have been better supported had Quality of Life studies been included in our study., Despite studies suggesting that the chance of becoming seizure-free after failing 2 AEDs is very low (roughly 3%), our study does demonstate that several of the newer AEDs carry a much higher likelihood of patients becoming seizure-free. Despite many patients not becoming seizure-free, retention rates at our center were also higher than other reports, suggesting better tolerance to the newer AEDs. Since all patients were under the care of the same authors at the same institution, there is less variability than comparing trials from different patients groups / centers. Despite this, the authors acknowledge that bias can still exist.,