A comprehensive study of the relation between serum concentrations, concentration ratios, and level/dose ratios of carbamazepine and its metabolites with age, weight, dose, and clearances in epileptic children.
We made a comprehensive study of the relation between age, weight, carbamazepine (CBZ) dose, total clearance (TC), and intrinsic clearance (IC) and concentrations, concentration ratios, and level/dose ratios of CBZ, carbamazepine-10,11-epoxide (CBZ-E) and trans-10,11-dihydroxy-10,11- dihydro-carbamazepine (CBZ-H) in a group of epileptic children receiving CBZ monotherapy. Body weight and age showed negative correlations with TC, IC, CBZ dose, and CBZ-E/CBZ and CBZ-H/CBZ concentration ratios, and had positive relation with CBZ, CBZ-E, and CBZ-H level/dose ratios. These results indicate decreased CBZ metabolism with patient maturity. Correlations between CBZ dose with TC, IC, and the concentration ratios of CBZ-E/CBZ, CBZ-H/CBZ-E, and CBZ-H/CBZ were positive. CBZ dose also had negative associations with CBZ and CBZ-E level/dose ratios, indicating dose-dependent autoinduction of CBZ metabolism. Our data suggest that weight, age, and CBZ dose have less influence on epoxide-hydrolase activities than on epoxidase activities. The CBZ-E/CBZ concentration ratio can be used as an indicator of the degree of autoinduction of CBZ metabolism, even in patients receiving CBZ monotherapy.
Liu
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Department of Laboratory, Texas Scottish Rite Hospital for Children, University of Texas Southwestern Medical Center, Dallas 75219.
Delgado
M R
MR
D000293:Adolescent; D000367:Age Factors; D001835:Body Weight; D002220:Carbamazepine / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004827:Epilepsy / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male
D002220:Carbamazepine; C004822:10,11-dihydro-10,11-dihydroxy-5H-dibenzazepine-5-carboxamide; C012227:carbamazepine epoxide