Analysis of influencing factors on monohydroxylated derivative of oxcarbazepine plasma concentration in children with epilepsy.

Purpose: This study aimed to investigate the factors affecting the plasma concentration of monohydroxylated derivative (MHD) of oxcarbazepine (OXC) in children with epilepsy.

Methods: We recruited 125 children with epilepsy who received OXC monotherapy. Among them, 16 single nucleotide polymorphisms were detected by MassARRAY genotyping technology to evaluate the influence of related factors on the plasma concentration of OXC monotherapy. MHD is the main active metabolite of OXC, and its plasma concentration was measured by high-performance liquid chromatography (HPLC).

Results: Bivariate correlation analysis revealed that concentration-dose ratio (CDR) increased with weight, and the corresponding maintenance dose decreased with weight (r=0.317, P=0.001 for CDR; r=-0.285, P=0.000 for OXC maintenance dose). The duration of seizure was found to be associated with CDR (0.90 ± 0.36 vs 0.74 ± 0.26 μg·kg/mg/mL for ≥6 years vs <1 year, P=0.028; 0.90 ± 0.36 vs 0.64 ± 0.21 μg·kg/mg/mL for ≥6 years vs 1-3 years, P=0.004; 0.90 ± 0.36 vs 0.69 ± 0.18 μg·kg/mg/mL for ≥6 years vs 3-6 years, P=0.031). The CDR of patients with ABCB1 rs1045642 mutation homozygous GG type is higher than heterozygous AG type (0.79 ± 0.30 vs 0.68 ± 0.20 μg·kg/mg/mL for AG vs GG, P=0.032).

Conclusion: This study clarified the association of weight, duration of seizure, and gene polymorphisms of ABCB1 rs1045642 with MHD plasma concentration in children with epilepsy.