CSF CONCENTRATIONS AND SERUM PROTEIN BINDING OF CARBAMAZEPINE AND CARBAMAZEPINE‐10, 11‐EPOXIDE IN EPILEPTIC PATIENTS

Abstract

Serum and CSF samples of patients receiving chronic carbamazepine treatment were analysed. Daily fluctuations in serum levels of carbamazepine and carbamazepine‐10, 11‐epoxide did not appear to be related to the dosage schedule, but some patients tended to have lower fluctuations when the carbamazepine was given more frequently. The epoxide/carbamazepine serum ratios varied greatly from patient to patient, and also fluctuated during the day for the same patient. Carbamazepine and carbamazepine‐10, 11‐epoxide were present in CSF in concentrations ranging from 19 to 34% and 26 to 71% of the serum concentrations, respectively. There was a significant relationship between the free fraction of both drugs evaluated in vivo and the CSF/serum ratios. The need for a careful evaluation of the possible clinical effect of the epoxide is stressed. 1976 The British Pharmacological Society