Drugs are Altered by the Body for Excretion – Alteration Efficiency Determines Duration of Effect

Oral Bioavailability

Drug Metabolism – A Two-Step Process

Cytochrome P-450 – a Phase I Oxidase

Cycle of P-450 Function



Drug Metabolism can Significantly Affect the Action of Many Drugs

Intrinsic Clearance

Factors Affecting Metabolism and Elimination – Can be Exogenous or Endogenous