The effect of age on pathways of drug metabolism in human liver.

The effect of age on some important pathways of drug metabolism in human liver biopsy specimens was examined. Five parameters were investigated: two microsomal mono-oxygenases; aldrin epoxidation and 7-ethoxycoumarin-O-de-ethylation; microsomal protein recovery; epoxide hydrolase activity and concentrations of reduced gluthatione. No correlation was observed between age and any of these measurements. It is concluded that, contrary to conventionally held views, impaired clearance of some drugs in the elderly is unlikely to be due to decreased hepatic microsomal enzyme specific activity. Any increase in adverse drug reactions in the elderly liver is unlikely to be due to impaired detoxification of reactive metabolites.