Understanding Adverse Drug Reactions: Definition & Types

According to the Food and Drug Administration (FDA), an adverse event is any undesirable experience associated with the use of a medical product in a patient. Adverse events are also referred to as side effects and are fairly common with use of prescription drugs.

Types of Adverse Drug Reactions

• According to the National Institutes of Health, adverse drug reactions are classified into six types: dose-related (Augmented), non-dose-related (Bizarre), dose-related and time-related (Chronic), time-related (Delayed), withdrawal (End of use) and failure of therapy (Failure).

Seriousness of Adverse Events

• According to the FDA, a serious adverse event occurs when one of the following happens: death, life-threatening event, hospitalization, disability, congenital anomaly or requirement of an intervention to prevent permanent impairment or damage.

Types of Drug Risk

• The iGuard Drug Risk Rating System is a color-based system that rates a drug's risk based on adverse reactions. Red means high risk; orange means elevated risk; yellow signifies guarded risk; blue means general risk; and green means low risk.

Side Effects vs. Adverse Events

• Many physicians refer to unwanted events as side effects; however, the phrase "adverse drug reaction" is more medically meaningful for drug effects that are unwanted, unpleasant, noxious or potentially harmful, according to Merck.com.

Examples of Adverse Drug Reactions

• Examples of adverse drug reactions include birth defects, diarrhea, vomiting, bleeding, fever, hair loss, liver damage and stroke.