Which drug is not a controlled substance?

Wellbutrin is not classified as a controlled substance because it does not have a high potential for abuse or dependence compared to the others listed. It is primarily used as an antidepressant and as a smoking cessation aid, functioning through mechanisms that do not produce the euphoria commonly associated with controlled substances. In contrast, Oxycontin, Percocet, and Ativan are all medications that carry risks of addiction, misuse, or dependence, categorizing them as controlled substances under the Controlled Substances Act. This classification helps regulate their prescribing and dispensing to ensure patient safety and to limit the potential for abuse.