Medication Error, Adverse Drug Event, and Adverse Drug Reaction

The terms medication error, adverse drug event, and adverse drug reaction denote related concepts (see Figure 1-1) and are often used incorrectly. To Err Is Human (IOM, 2000, p. 28) defined error and adverse event as follows:

An error is defined as the failure of a planned action to be completed as intended (i.e., error of execution), or the use of a wrong plan to achieve an aim (i.e., error of planning).

An adverse event is an injury caused by medical management rather than the underlying condition of the patient.

The Committee on Data Standards for Patient Safety was concerned that the phrase medical management did not embrace acts of omission. The committee gave considerable thought to expanding on these two definitions and produced the following (IOM, 2004, p. 30, 32):

An error is defined as the failure of a planned action to be completed as intended (i.e., error of execution), or the use of a wrong plan to achieve an aim (i.e., error of planning). An error may be an act of commission or an act of omission.

An adverse event results in unintended harm to the patient by an act of commission or omission rather than by the underlying disease or condition of the patient.

FIGURE 1-1 Relationship among medication errors, adverse drug events, and potential adverse drug events.

SOURCE: Gandhi et al., 2000.



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