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

PURPOSE: 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. METHODS: A narrative review of key studies defining and/or classifying medication harm terminology was undertaken. RESULTS: 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. CONCLUSION: 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.