Which drug listed is not classified under Schedule I?

Cocaine is the correct answer because it is classified as a Schedule II substance under the Controlled Substances Act. Schedule I drugs are defined as substances that have a high potential for abuse and no accepted medical use in the United States. Heroin, LSD, and Peyote are all considered Schedule I drugs due to their high potential for abuse and lack of accepted medical use.

In contrast, cocaine does have accepted medical uses, primarily as a local anesthetic, and is recognized as having therapeutic value, albeit it also presents a high potential for abuse. Thus, it fits into the Schedule II category, which includes substances that can be legally prescribed by healthcare professionals and have accepted medical applications but still carry significant risks of abuse and dependence. This distinction clarifies why cocaine is not included in the Schedule I classification.