Which of the following substances would be categorized as a Schedule IV drug?

Schedule IV drugs are substances that have a lower potential for abuse relative to drugs classified in Schedules I through III. They are typically recognized for having accepted medical uses and a lower risk of dependence. Soma, which is the brand name for carisoprodol, fits this description as a muscle relaxant that is prescribed for short-term relief of muscle spasms and discomfort.

In contrast, ketamine is classified as a Schedule III drug, primarily used as an anesthetic and sometimes for severe depression, but it has a recognized potential for abuse that is higher than that of Schedule IV substances. Peyote contains mescaline, which is a Schedule I substance due to its hallucinogenic properties and significant potential for abuse. Heroin is categorized as a Schedule I drug, as it has no accepted medical use in the United States and has a high potential for dependence and abuse.

Therefore, Soma is accurately categorized as a Schedule IV drug due to its medical applications and lower associated risks.