Enzyme Inhibition
The process by which a drug decreases the activity of drug-metabolizing enzymes, leading to reduced metabolism and elevated plasma concentrations of substrate drugs. Inhibition can be reversible (competitive or non-competitive) or irreversible (mechanism-based). Unlike induction, inhibition occurs rapidly, often within hours of co-administration.
Examples
- Ketoconazole: potent CYP3A4 inhibitor, increases midazolam AUC by 15-fold
- Fluoxetine: CYP2D6 inhibitor, raises codeine-to-morphine conversion failure
- Grapefruit juice: mechanism-based inhibitor of intestinal CYP3A4, increases felodipine bioavailability
Did You Know?
The process by which a drug decreases the activity of drug-metabolizing enzymes, leading to reduced metabolism and elevated plasma concentrations of substrate drugs. Inhibition can be reversible (competitive or non-competitive) …