Which designation has replaced the statement "Caution: Federal law prohibits dispensing without a prescription" for drug products that require a prescription in the United States?

The designation "Rx only" has replaced the statement "Caution: Federal law prohibits dispensing without a prescription" for drug products that require a prescription in the United States. This change was mandated by the Food and Drug Administration (FDA) to streamline labeling and clearly indicate that a prescription is necessary to obtain the medication.

The use of "Rx only" is more concise and easily recognizable by healthcare providers and patients alike, improving the clarity of labeling for prescription medications. It signifies that these drugs are not available for over-the-counter dispensing and thus should only be used under the supervision of a licensed healthcare professional. This helps ensure that patients receive appropriate medical guidance when using medications that may pose risks or require careful management.

The other options, while they communicate a similar concept, are not the standard language adopted by the FDA for prescription drug labeling. Therefore, they do not carry the same regulatory recognition or clarity as "Rx only."