### Question
How is the term unexpected serious risk defined?


### Answer
The term **unexpected serious risk** is defined in *21 U.S.C. § 355* as the following:

> a serious adverse drug experience that is not listed in the labeling of a drug, or that may be symptomatically and pathophysiologically related to an adverse drug experience identified in the labeling, but differs from such adverse drug experience because of greater severity, specificity, or prevalence

#### Citation:
  - *21 U.S.C. § 355*
  - Heading: **CHAPTER 9-FEDERAL FOOD, DRUG, AND COSMETIC ACT > SUBCHAPTER V-DRUGS AND DEVICES > Part A-Drugs and Devices**

