Adverse Drug Reactions, Safety, and Pharmacovigilance
This area covers the harms that medicines can cause and the systems built to detect, understand, and reduce them. It spans the recognition and causality assessment of adverse drug reactions, the human and system origins of medication errors, the post-marketing surveillance discipline of pharmacovigilance, and the organisational structures and safety culture that protect patients across the medication-use process.
Definition
Adverse drug reactions, safety, and pharmacovigilance is the body of knowledge and practice concerned with appreciable harm associated with medicines used at normal doses, with errors in the medication-use process, and with the detection, assessment, understanding, and prevention of drug-related problems at both the individual and population level.
Scope
The entry orients the reader to four connected topics: how individual adverse drug reactions are recognised and attributed; how medication errors arise and are intercepted; how spontaneous reporting and post-market surveillance generate safety signals; and how health systems organise themselves to make medication use safer. It treats drug safety as a methodological and organisational field, not as clinical guidance on any specific medicine.
Sub-topics
Key concepts
- Adverse drug reaction (ADR)
- Adverse drug event (ADE)
- Medication error
- Causality assessment
- Pharmacovigilance and signal detection
- Spontaneous reporting
- Medication safety systems and safety culture
- Preventability and the medication-use process
Mechanisms
Drug-related harm is studied along two axes. The first distinguishes the nature of the harm: an adverse drug reaction is an unintended, noxious response to a medicine at doses used in humans, whereas a medication error is a preventable failure in prescribing, dispensing, administration, or monitoring, and an adverse drug event is any harm associated with use whether or not an error or a pharmacological reaction was involved. The second axis is the level of analysis: the individual case (recognition and causality assessment) versus the population (surveillance that aggregates reports to detect signals). Bates and colleagues showed that many harmful events are linked to identifiable, often preventable, steps in the medication-use process, which connects the clinical and the systems perspectives.
Clinical relevance
Understanding drug-related harm underpins evidence appraisal, medication review, and the interpretation of safety information across the health professions. The topics in this area describe how harms are recognised, reported, and reduced at the level of systems and populations; they are a reference framework for that understanding and are not a basis for individual diagnostic or treatment decisions.
Epidemiology
Adverse drug reactions are a recurring cause of hospital admission and inpatient morbidity. A large prospective study reported that adverse drug reactions accounted for a substantial proportion of hospital admissions and that a majority of these were judged potentially avoidable, while early incidence studies documented frequent adverse drug events among hospitalised patients. These observations motivated the development of structured surveillance and safety systems.
History
Concern about drug safety intensified after the thalidomide disaster of the early 1960s, which prompted the World Health Organization to establish an international drug-monitoring programme and national centres to collect reports of suspected reactions. Over subsequent decades the field broadened from spontaneous reporting of adverse reactions toward a wider conception of medication safety that also encompasses preventable errors and the organisational conditions that produce them.
Key figures
- I. Ralph Edwards
- Jeffrey K. Aronson
- Munir Pirmohamed
- David W. Bates
- Lucian Leape
Related topics
Seminal works
- edwards-aronson-2000
- bates-1995
- pirmohamed-2004
Frequently asked questions
- What is the difference between an adverse drug reaction and a medication error?
- An adverse drug reaction is an unintended, harmful response to a medicine used at normal doses, whereas a medication error is a preventable failure somewhere in the medication-use process; an error may or may not cause harm, and harm may occur without any error.
- How does this area relate to pharmacovigilance?
- Pharmacovigilance is the surveillance discipline within this area that collects and analyses reports of suspected harm to detect safety signals across populations, complementing the individual-case work of recognising and assessing reactions.