Final answer:
Most prescription-only to OTC switches occur through a separate process called a New Drug Application (NDA). When a drug goes through the NDA process and is approved as safe and effective, it is available only by prescription by default. However, if the manufacturer wishes to make the drug available over-the-counter, they must go through another approval process to change its status.
Step-by-step explanation:
Most prescription-only to OTC switches occur through a separate process called a New Drug Application (NDA). When a drug goes through the NDA process and is approved as safe and effective, it is available only by prescription by default. However, if the manufacturer wishes to make the drug available over-the-counter, they must go through another approval process to change its status.