Types of Drug Interactions

Pharmacodynamic Drug Interactions

Pharmacodynamic: Mechanisms of action of one drug amplifies or diminishes the effect produced by mechanisms of action of another drug. a pharmacodynamic drug interaction is likely to produce a qualitative change in the patient's response (ie, a change in the nature of the response).

Pharmacokinetic Drug Interactions

Pharmacokinetic: Effect of one drug alters the pharmacokinetics of another, leading to a change in its effective concentration at its site(s) of action. pharmacokinetic drug interaction often produces the same result as would occur with a dose change and, thus, is something that can be expected when only using the affected drug. In contrast, pharmacokinetic interactions are more likely to present as a quantitative (ie, more or less) rather than a qualitative change in the patient's response