Objective assessment of neurotoxicity while shifting from carbamazepine to oxcarbazepine.
OBJECTIVE
Objective assessment of non-overt neurotoxicity of carbamazepine (CBZ) vs oxcarbazepine (OXC) in patients with difficult-to-treat partial epilepsy, who were resistant to CBZ treatment and were converted from CBZ monotherapy to OXC monotherapy.


METHODS
Therapeutically equivalent doses (150 mg OXC for every 100 mg CBZ) were compared in 20 adult patients. Neurological investigation, conventional and spectral EEG analysis, brainstem auditory evoked responses (BAER) were carried out in both treatment conditions. EEG and BAER data of 20 age-matched healthy controls helped interpretation. Primary target variables (electrophysiological parameters) were evaluated blindly.


RESULTS
There were no significant differences between treatment conditions concerning the neurological condition, lack of clinically evident neurotoxicity, seizure frequency and EEG spike frequency. OXC treatment was characterized by less delta, theta, and alpha power, more beta power, and significantly greater mean alpha frequency (P = 0.03 and 0.05 for the left and right occipital leads, respectively), than CBZ treatment. Interpeak latencies were prolonged in the CBZ condition as compared with normals (P = 0.01) and OXC (P = 0.02).


CONCLUSIONS
In this cohort of patients substitution of OXC for CBZ was associated with significant normalization of electrophysiological parameters, indicating decreasing neurotoxicity while shifting from CBZ to OXC monotherapy.
Clemens
B
B
Department of Neurology, Epilepsy Centre, Kenézy Gyula Memorial Hospital, Debrecen, Hungary. clemensb@freemail.hu
Ménes
A
A
Nagy
Z
Z
D000328:Adult; D000927:Anticonvulsants / Q000008:administration & dosage / Q000633:toxicity*; D001933:Brain Stem / Q000187:drug effects; D002220:Carbamazepine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000633:toxicity*; D002540:Cerebral Cortex / Q000187:drug effects; D004351:Drug Resistance; D004569:Electroencephalography / Q000187:drug effects; D004828:Epilepsies, Partial / Q000188:drug therapy* / Q000523:psychology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination / Q000187:drug effects; D000078330:Oxcarbazepine; D011446:Prospective Studies; D012815:Signal Processing, Computer-Assisted; D013375:Substance Withdrawal Syndrome / Q000175:diagnosis* / Q000523:psychology; D013810:Therapeutic Equivalency; D016896:Treatment Outcome
D000927:Anticonvulsants; D002220:Carbamazepine; D000078330:Oxcarbazepine