CONCENTRATIONS OF CARBAMAZEPINE AND CARBAMAZEPINE-10,11-EPOXIDE IN SERUM, BRAIN-TUMORS AND PARATUMOROUS CORTEX - A PROSPECTIVE-STUDY OF 37 NEUROSURGICALLY TREATED EPILEPTIC PATIENTS

Concentrations of carbamazepine (CBZ) and its metabolite carbamazepine -10,11-epoxide (CE) were determined in serum (free and total), brain t umors and paratumorous cortex from 37 epileptic patients. Tumor biopsi es were available from 25 different gliomas, 5 hamartomas and 1 angiom a. The free serum concentrations of CBZ and CE were highly correlated with the corresponding paratumorous concentrations (r = 0.94 and r = 0 .93) and to a lower extent with the tumorous concentrations (r = 0.78 and r = 0.75). For CBZ the concentration ratios paratumorous cortex/se rum free and tumor/serum free showed no significant differences betwee n CBZ-resistant and -nonresistant patients. Apart from histological gr ade a significant influence of type and site of the tumors on their CB Z and CE concentration was not recognizable. The results indicate that resistance to CBZ therapy cannot be sufficiently explained by decreas ed paratumorous or tumorous levels of CBZ and CE.