Differences between the concentrations of antiepileptic drugs in normal and pathological human brain.

The concentrations of antiepileptic drugs in histologically normal and pathological brain tissues were investigated in 6 patients submitted to surgery. No significant difference for phenobarbital and phenytoin was found between normal and scar tissue, whereas there was a trend to concentration in tumour tissue (meningioma and glioma) of phenobarbital, phenytoin and carbamazepine. Alteration in the vascular supply and pathological changes at cellular and subcellular levels could be responsible for the differences in the distribution of the drugs. The possible clinical relevance of the preferential concentration of the drugs in tumour tissue is discussed.