Which of the following is an example of a Schedule III drug?

• A. Heroin
• B. Ketamine
• C. Cocaine
• D. LSD

Answer: (B)

Drug scheduling under the Controlled Substances Act classifies drugs by medical use and potential for abuse. Schedule III includes substances that have an accepted medical use and a lower potential for abuse and dependence than Schedule II drugs. Ketamine fits here because it is used medically as an anesthetic and analgesic, and while it can be abused, its abuse potential is lower than that of substances in Schedule II. This combination of accepted medical use with moderate abuse potential is what places ketamine in Schedule III.

For contrast: heroin is listed as Schedule I due to no accepted medical use and high abuse potential; cocaine is Schedule II—has medical uses but a high potential for abuse; LSD is Schedule I as well—no accepted medical use and high abuse potential.