Final answer:
The NDC on a label indicates registration but not necessarily FDA approval, which involves a detailed review process and after which the drug is deemed safe and effective if used as directed.
Step-by-step explanation:
The presence of a National Drug Code (NDC) on a drug's label indicates that the drug has been registered with the Food and Drug Administration (FDA). However, it does not always mean the drug has been approved by the FDA. The NDC is a unique identifier for medications intended for human use. All marketed drug products are required to have an NDC which serves primarily as an inventory tool. Approval of drugs by the FDA is a separate process, which involves a thorough review of safety and efficacy through the New Drug Application (NDA) for new drugs, and corresponding applications for generic drugs and over-the-counter drugs. Once a drug is approved by the FDA, it is considered "safe and effective when used as directed." The drug must also meet requirements for manufacturing and labeling before it can be marketed. Additionally, the FDA regulates the advertising and promotions of drugs, ensuring that companies only promote drugs for the approved indications and with a fair balance between benefits and risks.