Which option is not a characteristic of Schedule I drugs?

• A. High abuse potential
• B. No accepted medical use in the U.S.
• C. A lack of accepted safety under medical supervision
• D. High therapeutic index

Answer: (D)

Classification of drugs into schedules is based on abuse potential, medical usefulness, and safety under medical supervision. Schedule I substances are defined by very high abuse potential, no accepted medical use in the United States, and a lack of accepted safety for use under medical supervision. A high therapeutic index means a wide safety margin between effective and toxic doses, which implies relative safety. That characteristic does not fit Schedule I drugs, which are considered unsafe and lacking accepted medical use. So the option describing a high therapeutic index is not a characteristic of Schedule I substances.