Relationship between mono-hydroxy-carbazepine serum concentrations and adverse effects in patients on oxcarbazepine monotherapy

AbstractPurposeTo evaluate the relationship between serum concentrations of mono-hydroxy-carbazepine (MHD), the main metabolite of oxcarbazepine (OXC), and the occurrence of adverse effects (AE) in a large group of patients on OXC monotherapy.MethodsAn antiepileptic drug (AED) therapeutic drug monitoring (TDM) database was analyzed especially with regard to OXC dosage, MHD serum concentration, and the occurrence of AE. In total, 893 blood samples of 442 patients were included in this retrospective study. The statistical evaluation was performed by means of Kaplan-Meier estimates, log-rank tests and generalized estimating equations (GEE).ResultsAt least one AE was reported in 78 (17.6%) of the 442 patients. At MHD serum concentrations of 30.0μg/ml and 43.7μg/ml and OXC dosages of 33.1mg/kg and 62.3mg/kg, 25% and 75% of patients, respectively, experienced at least one AE. Log-rank tests indicated that younger patients (<18 years) may be able to tolerate higher MHD serum levels (p=0.006) and higher OXC dosages per body weight (p