Which of the following is an example of a Schedule I Controlled Substance?

Heroin is classified as a Schedule I Controlled Substance under both federal law and Arkansas state law. Schedule I substances are characterized by having a high potential for abuse and no accepted medical use in treatment in the United States. This classification underscores the significant risks associated with these substances, such as severe psychological or physical dependence.

In the context of the other substances listed, oxycodone, hydrocodone, and cocaine are not categorized as Schedule I. Oxycodone and hydrocodone are both classified as Schedule II substances, which indicates that they have accepted medical uses but also carry a high potential for abuse and dependence. Cocaine is classified as a Schedule II substance as well, due to its accepted medical use (mainly as a local anesthetic in certain medical situations), despite its high potential for abuse. This differentiation in classification reflects the legal understanding of the risks and medical applications associated with each substance.