Prescription Drug (Rx)

Key facts

Legal basis

FD&C Act Section 503(b), added by the Durham-Humphrey Amendment of 1951

Required label statement

Rx only

Labeling format rules

21 CFR 201.56 and 201.57

Who can prescribe

Set by state law and varies by profession

Controlled substances

Prescriber also needs a DEA registration

What is a prescription drug?

Federal law divides drugs into prescription and nonprescription categories. A drug is prescription-only when, because of its toxicity, potential for harm, method of use or the measures needed to use it, it is not safe except under the supervision of a licensed practitioner, or when its FDA approval limits it to prescription use.

The Rx symbol comes from the Latin word recipe, meaning take. Prescription drugs include most brand-name and generic medicines and nearly all biologics. The older term legend drug refers to the required prescription legend on the label.

Which professionals can prescribe, and what they can prescribe, is set by state law. Physicians, nurse practitioners, physician assistants, dentists and podiatrists commonly hold some prescriptive authority, with limits that differ by state.

How prescription drugs are regulated

Prescription status brings federal rules at each step from approval to dispensing:

• Approval: the FDA approves prescription drugs through a New Drug Application (NDA), Abbreviated New Drug Application (ANDA) or Biologics License Application (BLA), and the approval defines the conditions of use.
• Labeling: prescribing information for newer drugs follows a standard format with Highlights and numbered sections such as Indications and Usage, Dosage and Administration, and Warnings and Precautions.
• Advertising: the FDA regulates prescription drug advertising, including direct-to-consumer ads, which must present risk information in fair balance with benefits.
• Dispensing: pharmacies dispense against a valid prescription under state pharmacy law, and controlled substances add Drug Enforcement Administration (DEA) rules.
• Supply chain: the Drug Supply Chain Security Act of 2013 requires product tracing for most prescription drugs.

Why prescription drug status matters

The prescription requirement is what makes prescriber-level drug data possible:

• Claims data: each fill generates a pharmacy claim with the NDC, prescriber NPI and quantity, the foundation of Medicare Part D prescriber data and commercial prescription data.
• Coverage: Medicare Part D and Medicaid outpatient drug benefits are built around prescription drugs, and most OTC products fall outside them.
• Commercial targeting: because a practitioner must write the order, manufacturers direct sales and medical education at prescribers, identified by NPI and specialty.
• Promotion compliance: manufacturer promotion must stay consistent with FDA-approved labeling and meet FDA advertising rules.