Which statement best defines a medication error?

• A. A preventable event that leads to inappropriate med use or patient harm
• B. An adverse drug reaction
• C. An intentional change in therapy by physician
• D. A resolved issue

Answer: (A)

Medication error means a preventable event in the medication-use process that leads to inappropriate medication use or patient harm. It can happen at any step—prescribing, transcribing, dispensing, administering, or monitoring—and the key is that it could have been avoided with safer systems and practices. This distinguishes it from an adverse drug reaction, which is harm that occurs from a drug even when it’s used correctly and without any error in the process. It also differs from an intentional change in therapy by a clinician, which is a deliberate clinical decision rather than a preventable mistake. A “resolved issue” doesn’t define an error, since medication errors refer to the preventable event itself, not just something that has been fixed.