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Learning Objectives

After completing this chapter, the reader will be able to

  • Define adverse drug reactions (ADRs).

  • Discuss the impact of ADRs on health care systems and patients.

  • Explain methods for determining causality and probability of an ADR.

  • Identify specialty drug information resources that can be used to locate information related to ADRs.

  • Classify ADRs based on type and severity.

  • Use guidelines from national organizations to implement an ADR reporting program.

  • Describe the use of technology in ADR monitoring and reporting.

  • Explain when, where, and how to report an ADR to the U.S. Food and Drug Administration (FDA).

  • Explain how to report adverse reactions related to dietary supplements and vaccines.

Key Concepts

  • 1 Adverse drug reaction (ADR) refers to any unexpected, unintended, undesired, or excessive response to a medicine.

  • 2 One of the first steps in establishing an ADR program is to define what each facility or organization categorizes as ADRs.

  • 3 Several algorithms have been published that try to incorporate information about an ADR into a more objective form.

  • 4 Communication is a critical component throughout the ADR monitoring process.

  • 5 Technology plays an important role in monitoring, identifying, and minimizing ADRs.

  • 6 ADR surveillance serves as a means to primarily provide early signals about possible problems with a medication.


The terminology surrounding adverse drug reactions (ADRs) is often confusing. All adverse drug events (ADEs), ADRs, and medication errors fall under the umbrella of medication misadventures. Medication misadventure is a very broad term, referring to any iatrogenic hazard or incident associated with medications. An ADE is the next broadest term, and refers to any injury caused by a medicine. An ADE encompasses all ADRs, including allergic and idiosyncratic reactions, as well as medication errors that result in harm to a patient.1-5 ADRs and medication errors are the most specific terms. 1 Adverse drug reaction refers to any unexpected, unintended, undesired, or excessive response to a medicine. A medication error is any preventable event that has the potential to lead to inappropriate medication use or patient harm.1 Figure 17-1 shows one way of graphically classifying these terms. Many of these concepts will be explored in greater depth elsewhere in this text as well as in Chapter 18 Medication Misadventures II: Medication and Patient Safety. The present chapter focuses on ADRs, highlighting the impact of ADRs, pertinent definitions and classifications, specialty drug information resources, ADR reporting systems, and future approaches to detecting and managing ADRs.

Figure 17–1.

Relationship among medication misadventures, adverse drug events, medication errors, and adverse drug reactions. (Adapted from Bates DW, et al. Relationship between medication and errors and adverse drug events. J Gen Intern Med. 1995 Apr;10(4):199-205.)

Impact of Adverse Drug Reactions

All medications, including the inactive ingredients of ...

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