CC21 – Adverse drug reaction and adverse drug event
CC21. Adverse drug reaction and adverse drug event are terms that refer to harmful or undesirable response to a drug.
21.1. An adverse drug event is harm caused by appropriate or inappropriate use of a drug whereas adverse drug reactions are a subset of these events, wherein harm is directly caused by a drug under appropriate use (i.e., at normal doses).
21.2. Adverse drug reactions are traditionally classified as predictable/dose-dependent (Type A) or unpredictable/idiosyncratic (Type B).
21.3. Type A adverse drug reactions are often inherently linked to the pharmacological effects of a drug and show a dose–response relationship and, thus, can be predicted.
21.4. Type B adverse drug reactions are idiosyncratic and have no link with the pharmacological mechanism of action and are thus unpredictable.
21.5. Adverse reactions can be impacted by changes in plasma concentration due to drug–drug interactions, drug–food interactions, changes in metabolism and additional disease states.
21.6. Adverse drug reactions may require the dose of the drug to be reduced or substituted with a different drug.
