How can the FDA switch a drug from OTC to Rx only?

The correct choice reflects how the FDA assesses the safety and regulation of over-the-counter (OTC) medications. When considering switching a drug from OTC to prescription-only (Rx), the FDA typically focuses on the safety of the drug when used without supervision. This means that if evidence suggests that a drug poses significant safety risks—such as serious side effects, potential for misuse, or complications arising from improper use—this could warrant moving it to prescription status where it would be used under a healthcare provider’s supervision.

In contrast, factors such as price or potential for addiction, while important, do not directly affect the regulatory classification in the same way. For instance, a higher price alone does not indicate whether a drug requires professional oversight for safe use, nor does demonstrating that a drug could be addictive automatically justify a switch to Rx-only status. Additionally, while showing effectiveness for complicated conditions may support its value in a prescription context, the decision hinges more on the implications for safety rather than on the condition it treats. Thus, the paramount concern guiding the FDA's classification decision is whether a drug can be safely used without professional supervision.