Liver size and indices of drug metabolism in epileptics

1 The relationship between liver size and in vivo (antipyrine kinetics) and in vitro (cytochrome P‐450) drug metabolism was investigated in twenty‐one epileptics on long‐term anticonvulsant therapy and in controls. 2 The epileptics exhibited significant enlargement of the liver and enhancement of drug metabolism compared to the controls. 3 Liver size correlated to antipyrine kinetics only in controls. Concentration of cytochrome P‐450 in liver biopsy specimens correlated with liver size neither in controls nor in epileptics. 4 The total hepatic cytochrome P‐450, estimated on the basis of liver weight and cytochrome P‐450 concentration of biopsy samples, correlated linearly with antipyrine kinetics, except in patients with the most severely disturbed liver architecture. 5 Measurement of liver size is essential when comparing in vivo and in vitro drug metabolism, but the changes in liver histology are also of great importance.