Carbamazepine 10,11‐epoxide in children.

Abstract

Concentrations of carbamazepine (CBZ) and its 10,11‐epoxide metabolite (CBZ‐E) were measured in simultaneously collected plasma and mixed saliva samples from 15 children (aged 1‐13 years). Saliva concentrations of CBZ and CBZ‐E were measured in hourly samples taken from six of these children during dose intervals whilst on different dose or dose‐frequency regimens. Saliva and plasma CBZ (r = 0.91; P less than 0.001) and CBZ‐E (r = 0.91; P less than 0.001) concentrations were significantly correlated. The mean +/‐ s.d. steady state CBZ‐E/CBZ concentration ratio in the six children was 0.40 +/‐ 0.21 and was similar at all times within the 12 h dose interval. The mean +/‐ s.d. percentage fluctuation of the combined CBZ + CBZ‐E (103.0 +/‐28.9) was significantly less than that of CBZ‐E (145.5 +/‐ 52.8) but not CBZ (109.6 +/‐ 31.1). If CBZ and CBZ‐E have equipotent anticonvulsant activity in man, the contribution of CBZ‐E approximates to 30% of total anticonvulsant effect in children taking CBZ alone. 1984 The British Pharmacological Society