drug metabolism

Last reviewed 01/2018

Drug metabolism may have the following effects:

  • prodrugs activated:
    • improved absorption
    • improved distribution - L-dopa vs dopamine
    • avoiding adverse effect in gut
  • active drug converted to other active compounds:
    • diamorphine to morphine
    • diazepam to desmethyliazepam
    • lignocaine to toxic metabolites
    • procainamide to n-acetylprocainamide - less toxic
  • active drugs inactivated:
    • phase I - oxidation, reduction, hydrolysis,
    • phase II - conjugation - sulphatation, glucuronidation, methylation etc.

  • factors which may alter metabolism include:
    • genetic
    • drugs
    • hepatic blood flow
    • liver disease - must be severe, but shunting is powerful
    • age - reduced metabolic capacity in young and elderly