Common concepts and terms in pharmacovigilance

A small selection of the main technical terms and specialised verbal usage in pharmacovigilance, defined in everyday language, with some additional explanatory notes. A full list of formal definitions can be found in the glossary

Adverse drug reaction (ADR): A harmful effect suspected to be caused by a drug. This term has been used quite loosely to include all kinds of adverse events, many of which are not ‘reactions’ in the strict sense at all, and have not been subject to any assessment of causality. The term is properly reserved for late-stage analysis when the association between a medicine and an adverse effect has moved beyond 'unmeasurable' or 'uncertain'.
Adverse effect: A negative or harmful patient outcome that seems to be associated with treatment, including there being no effect at all.
Adverse event: Any negative or harmful occurrence that takes place during treatment, that may or may not be associated with a medicine.
A fall could be such an event that may – or may not – have any association with a medicine.
Benefit: (a) positive therapeutic effects of treatment in an individual; (b) positive health, social or psychological effects of treatment from the patient’s perspective. 
Benefit-risk: more accurately, benefit-harm; a description of both positive and negative effects of a medicine and the likelihood of their occurrence, as far as they are known, as perceived by an individual. 
This is the critical information that health professionals and patients need to make wise therapeutic decisions. The perspectives of professionals and patients on the issues may differ.
Effectiveness: A measure of the chances or odds (probability) of a medicine working positively as expected for patients.
Effectiveness-risk: A comparison of the statistical chances (probability) of a medicine working as expected and/or causing harm. This is the correct term for this comparison, not ‘benefit-risk’, which is a logically mismatched pair.
Efficacy: A measure of the extent to which a chemical substance or medicine works positively under laboratory conditions and in a selected group of patients.
Harm: The damage or injury that is or might be caused by a medicine, including death. The concept extends to social and psychological damage or impairment, especially from the patient’s perspective.
Hazard: The intrinsic chemical or biological characteristics of a medicine or its use that have the potential to cause harm. 
Individual case safety report (ICSR): Reports sent by health professionals or patients when an adverse effect has occurred in a patient taking one or more medicines. These have also been referred to as adverse drug reaction (ADR) reports or adverse event (AE) reports. See also Pharmacovigilance reporting systems.
Risk: The statistical probability of harm being caused.
Serious: An adverse event or reaction that results in death; requires hospitalisation or extension of hospital stay; results in persistent or significant disability or incapacity; is life-threatening.
Note. This contrasts with severe, which is used to indicate intensity (as in severe headache).
Side-effect: Any unintended outcome that seems to be associated with treatment, including negative or positive effects. This term is often used in patient information and other contexts, when ‘adverse effect’ is the strictly correct term.
Pharmacovigilance reporting systems: The core data-generating system of pharmacovigilance, relying on healthcare professionals and patients to identify and report any suspected adverse effects from medicines to their local or national pharmacovigilance centre or to the manufacturer.
Also referred to as Postmarketing/Safety surveillance, or Spontaneous reporting systems

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Last modified on: February 13, 2017