Which of the following substances is considered Schedule V?

Diphenoxylate with atropine is classified as a Schedule V substance primarily because it is a combination medication that is specifically used to treat diarrhea. The potential for abuse with Schedule V substances is lower compared to those in higher schedules, like Schedule II or III. This lower potential for abuse is partly due to the presence of atropine, which discourages misuse and helps to mitigate the effects when taken in high doses.

In the controlled substances scheduling system, Schedule V drugs may contain limited quantities of certain narcotics and are generally considered to have a lower risk of physical dependence compared to medications found in higher schedules. This classification reflects both the therapeutic use of the drug and the recognition that, while it can have psychoactive effects, it is less likely to lead to addiction when used as directed.

Other substances listed, such as oxycodone, methylphenidate, and hydrocodone, are classified in higher schedules due to their increased potential for abuse and dependence, which is why they are not included in Schedule V.