What is an example of a Schedule III drug?

Fiorenal is an appropriate example of a Schedule III drug because it contains a combination of butalbital, acetaminophen, and caffeine. Schedule III drugs in the Controlled Substances Act are characterized by having a moderate potential for abuse compared to Schedule I and II substances. The abuse potential leads to physical dependence or high psychological dependence, but it is lower than that associated with drugs in Schedules I and II. Fiorenal, specifically due to its butalbital content, fits into this category as its usage can lead to dependence, yet it is recognized as having accepted medical uses.

The other choices do not fit into the Schedule III classification. Clonazepam and Diazepam are classified as Schedule IV drugs due to their lower abuse potential and accepted medical uses, typically in the treatment of anxiety and seizures. Phenobarbital is a Schedule IV drug as well, given its uses in treating seizures and other conditions, but it is recognized as having a lower abuse potential than what would qualify it for Schedule III. Thus, understanding the classifications of controlled substances, along with their medical uses and potential for abuse, clarifies why Fiorenal is designated as a Schedule III drug.