Temporal pattern of oxcarbazepine and phenytoin withdrawal seizures during epilepsy monitoring.
OBJECTIVE
To compare the temporal pattern of seizures after acute withdrawal of oxcarbazepine (OXC) and phenytoin (PHT) in the epilepsy monitoring unit (EMU).


METHODS
We identified all epilepsy patients admitted to our EMU on OXC or PHT monotherapy, over a period of 5 years. The OXC taper usually occurred over 2 days while PHT was abruptly discontinued on admission day. For each patient, we recorded the number and type of seizures for each EMU day. We used Poisson regression models to estimate daily seizure frequency separately for complex partial seizures (CPSs) and generalized tonic-clonic seizures (GTCSs).


RESULTS
Forty patients were admitted on OXC and 32 on PHT monotherapy. The temporal distribution of seizures varied between the two groups. The first GTCS was more likely to occur in the first 2 days of monitoring for the OXC group (p<0.046). There was a higher frequency of GTCS on day 2 of admission in the OXC group (p=0.011). The groups did not differ in the pattern of CPS.


CONCLUSIONS
OXC is disproportionately associated with increased GTCS in the first 2 days after acute withdrawal. The early peak of GTCS favors a rebound phenomenon in addition to loss of therapeutic effect.
Azar
Nabil J
NJ
Department of Neurology, Vanderbilt University Medical Center, A-0118 MCN 2551, Nashville, TN 37232-2551, United States.
Wang
Lily
L
Song
Yanna
Y
Abou-Khalil
Bassel W
BW
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects*; D002220:Carbamazepine / Q000009:adverse effects / Q000031:analogs & derivatives*; D016022:Case-Control Studies; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000188:drug therapy; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D000078330:Oxcarbazepine; D010672:Phenytoin / Q000009:adverse effects*; D016012:Poisson Distribution; D012189:Retrospective Studies; D012640:Seizures / Q000139:chemically induced*; D013375:Substance Withdrawal Syndrome / Q000209:etiology*
D000927:Anticonvulsants; D002220:Carbamazepine; D010672:Phenytoin; D000078330:Oxcarbazepine