Clinical application of blood concentration monitoring of active metabolite of oxcarbazepine in childhood focal epilepsy

Abstract

Objective To investigate the value of blood concentration monitoring of 10-monohydroxy carbamazepine (MHD), the active metabolite of oxcarbazepine (OXC), in the treatment ofchildhood focal epilepsy. Methods A total of 110 children with focal epilepsy took OXC for 3 months and then the MHD concentrations were determined by high pressure liquid chromatography (HPLC).  Results The average dose of OXC in 110 children was (25.52 ± 7.28) mg/(kg·d) and the valley point concentration of MHD was 7.00 (4.95, 10.50) mg/L, and 89 cases (80.91%) < 12 mg/L. A linear relationship between MHD valley point concentration and OXC dose (r_s = 0.337, P = 0.000) was shown by Spearman rank correlation analysis. The dosage of OXC for older ( > 7 years) children was significantly lower than that of younger (≤ 7 years) children [(23.13 ± 5.56) mg/(kg·d) vs. (28.09 ± 8.06) mg/(kg·d); t = 3.778, P = 0.000], while there was no significant difference between the concentration of children with different sexes (t = 1.067, P = 0.288), between children with and without drug resistant epilepsy (DRE; t = 1.417, P = 0.159) and between monotherapy and combination drug therapy (t = 1.671, P = 0.098). The MHD valley point concentration in DRE group was lower than that of non-DRE group [6.32 (3.05, 8.58) mg/L vs. 8.30 (5.75, 10.85) mg/L; Z = 2.380, P = 0.017], while there was no significant difference between the concentration of children with different sexes (Z = 0.604, P = 0.546), between older and younger children (Z = 0.179, P = 0.858) and between monotherapy and combination drug therapy (Z = 1.583, P = 0.113).  Conclusions There is a linear relationship between MHD steady state valley point concentration and the dose of OXC. To achieve the same MHD level, the younger children need to take a larger dose of OXC. When OXC is used to treat drug resistant focal epilepsy in children, the dosage should be adjusted according to the monitoring of blood concentration of MHD.

DOI: 10.3969/j.issn.1672-6731.2018.06.009