Pharmacodynamics

Pharmacodynamics is the study of the relationship between the concentration of drug at the site of action and the biochemical and physiological effect. The response of the receptor may be affected by the presence of drugs competing for the same receptor, the functional state of the receptor or pathophysiological factors such as hypokalaemia. Interindividual variability in pharmacodynamics may be genetic or reflect the development of tolerance to the drug with continued exposure. High pharmacodynamic variability severely limits the usefulness of monitoring drug concentrations as they are likely to give a poor indication of the effectiven