Final answer:
A brand and generic product are classified as interchangeable when they share the same active ingredients, strength, and dosage form.
Step-by-step explanation:
A brand and generic product must be identical in active ingredients, strength, and dosage form to be classified as interchangeable. This is necessary to ensure that the generic drug can be used as a direct substitute for the brand-name drug it replicates. For the approval of a generic drug, the U.S. Food and Drug Administration (FDA) requires scientific evidence that the generic is therapeutically equivalent to the brand-name product, which is accomplished through an Abbreviated New Drug Application (ANDA).
It is important to note that while generics must be bioequivalent in active ingredients, they may contain different inactive ingredients such as fillers or dyes. Nevertheless, these differences do not affect the therapeutic action of the drug. As generics tend to be less expensive and widely used, they play a significant role in healthcare by making treatments more accessible.