When can a previously approved drug be considered a new drug?

A previously approved drug can be considered a new drug when a new active ingredient is added. The definition of a "new drug" is rooted in the Federal Food, Drug, and Cosmetic Act, which indicates that any drug that contains a new substance as an active ingredient, or a combination of active ingredients, is classified as a new drug. This reclassification occurs because the introduction of a new active ingredient can lead to changes in the drug's safety and effectiveness profile, thus requiring additional evaluation by the FDA.

The addition of new active ingredients necessitates new clinical data to assess the drug's safety and efficacy, meaning the product does not have the same regulatory status as its predecessor. Therefore, the understanding of what constitutes a new drug hinges on the specific changes made to its formulation and active components.

In contrast, changes such as marketing by a different manufacturer do not inherently meet the criteria for a new drug status since the FDA’s focus is more on the formula of the drug rather than the identity of the manufacturer. Similarly, proof of efficacy pertains to the drug's application and regulatory approval process, not the status of the drug itself. Lastly, additional advertising does not change the drug's formulation or its active ingredients; therefore, it cannot qualify as a reason