Defining and classifying terminology for medication harm: a call for consensus.

The multiplicity in terms and definitions of medication-related harm has been a long-standing challenge for health researchers, clinicians, and regulatory bodies. The purpose of this narrative review was to report the diversity of terms; compare definitions, classifications, and models describing medication harm; and suggest which may be useful in both clinical practice and the research setting. A narrative review of key studies defining and/or classifying medication harm terminology was undertaken. This review found that numerous terms are used to describe medication harm, and that there is a lack of consistency in current definitions, classifications, and applications. This lack of consistency applied across clinical jurisdictions and regulatory terminologies. A number of limitations in current definitions and classifications were identified. These included the exclusion of key types of medication harm events, ambiguous wording, and a lack of clarity and consensus on subclassifications. In general, there was some overlap in key models from the literature and these were presented to describe similarities and differences. Without uniformity quantifying, comparing, combining, or extrapolating medication harm data, such as a rate of harm in a specific population, is a challenge for those involved in medication safety and pharmacovigilance. There is a pressing need for further discussion and international consensus on this topic. Adoption of standard descriptors by practitioner groups, regulatory and policy organisations would foster quality improvement and patient safety.