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

Objective To investigate the value of blood concentration monitoring of 10 - monohydroxy carbamazepine (MHD), the active metabolite of oxcarbazepine (OXC), in the treatment of childhood 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 = 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. [ABSTRACT FROM AUTHOR]