Abstracts

Rationale: Increased seizure frequency has been reported to occur when transitioning from carbamazepine (CBZ) to alternated AED. The period of increased seizure frequency is the first 2 weeks after stopping CBZ (DeToledo) and this was not observed when converting from phenytoin (PHT), valproate (VPA) or felbamate (FBM). The question to address is whether withdrawal seizures occur when converting CBZ or OXC to eslicarbazepine acetate (ESL). Methods: We re-analyzed the pooled data from two conversion to monotherapy clinical trial which included patients who converted from AED regimen with CBZ (+CBZ) and patient with AED regimen not containing CBZ (-CBZ) to monotherapy with eslicarbazepine acetate (ESL). AED regimen did include other drugs with putative similar mechanism of inhibition of Voltage Gated Sodium Channel (VGSCi). Study design was same for both and consisted of 2-week ESL titration, 6-week baseline AED taper [concomitant AEDs withdrawn], and 10-week ESL monotherapy Results: Outcomes in 365 patients were evaluated for daily seizure frequency over the duration of the blinded treatment phases.  Patients were separated into four groups, 1) convert from +CBZ to Esl 1200 mg QD, 2) converted from CBZ+ to Esl 1600 mg QD, 3) converted from -CBZ to Esli 1200 mg QD and 4) -CBZ to Esli 1600 mg QD.  Mean number of daily seizure for each group was calculated and compared.  No difference was found between the four groups (Graph 1).  Conclusions: The seizure exacerbation which occurs when tapering patients off CBZ was not observed converting  patients to ESL.     References DeToledo JC, Ramsay RE, Lowe MR, Greiner M, and Garofalo EA. Increased seizures after discontinuing carbamazepine: results from the Gabapentin Monotherapy Trial. Ther Drug Monit. 2000;22(6), 2000. Azar NJ, Wright AT, Wang L, Song Y, Abou-Khalil BW. Generalized tonic clonic seizures after acute oxcarbazepine withdrawal.  Neurology. 2008;70:2187-2188Duncan JS, Shorvon SD, Trimble MR. Discontinuation of phenytoin, carbamazepine and valproate in patients with active epilepsy.  Epilepsia. 1990;31:324–333.Marciani MG, Gotman J, Anderman F, et al. Patterns of seizure activation after withdrawal of antiepileptic medication. Neurology. 1985;35:1537–1543.Pazdera L, Sperling MR, Harvey JH, Sam MC, Strom LA, Blum D, Grinnell T, Cheng H.  Efficacy and safety of eslicarbazepine acetate monotherapy in patients converting from carbamazepine..  Epilepsia. 2018;59:704–714. Funding: None