Key Principles of Pharmacology


2. Pharmacokinetics

Pharmacokinetics (PK) is the study of the effect the body has on a medicine.

In other words, pharmacokinetics studies four major mechanisms usually identified in many text books with the acronym ADME:
  • Absorption: How the medicine gets into the body
  • Distribution: Where the medicine goes in the body
  • Metabolism: How the body chemically modifies the medicine
  • Excretion: How the body eliminates the medicine
We need to consider the above four elements when talking about the pharmacology of a certain medicine in animals and in humans. More importantly, together, they will provide data indicating the difference between beneficial and negative (toxic) effects. These ADME elements mainly help to predict the safety and tolerability of an investigational compound in humans.

Illustrated chart of the principles of ADME

Figure 3: Illustrated chart of the principles of ADME