Pharmacology Teaching and Research

Online Lecture: Pharmacokinetics.

Drug Metabolism and Drug Elimination

Drug metabolism is the term used to describe the biotransformation of pharmaceutical substances in the body so that they can be eliminated more easily.

The majority of metabolic processes that involve drugs occur in the liver, as the enzymes that facilitate the reactions are concentrated there.                        

The purpose of metabolism in the body is usually to change the chemical structure of the substance, to increase the ease with which it can be excreted from the body.

Drugs are metabolized through various reactions including:

Oxidation, Reduction, Hydrolysis, Hydration, Conjugation, Condensation and Isomerization.


In most cases, when a drug is metabolized it becomes inactivated.

However, the metabolites of some drugs are pharmacologically active and exert an effect on the body.

In fact, the active metabolite of some medications is responsible for the principal action of the drug. In this case, the drug formulation is referred to as a prodrug.

Click below for a Presentation - Drug Metabolism and Drug Elimination.