A publication by the FDA that identifies drugs approved on the basis of safety, effectiveness, and therapeutic equivalence under the Federal Food, Drug, and Cosmetic Act. It contains patent and exclusivity information. Biological products are not listed in the Orange Book, but are listed in the Purple Book (see Purple Book).

An orphan drug is a drug for a rare disease or condition. Some rare disease treatments have been “orphaned” or discontinued because there was not enough financial incentive to continue development or production. The Orphan Drug Act incentivizes drug development for rare diseases.

The OOP maximum is a predetermined amount that an individual pays during a plan year before their health plan sponsor pays 100% of their covered medical treatments and services.

OTC drug products are those drugs that are available to consumers without a prescription. There are more than 80 therapeutic categories of OTC drugs, ranging from acne drug products to weight control drug and birth control products. As with prescription drugs, the Center for Drug Evaluation and Research (CDER) within FDA oversees OTC drugs to ensure that they are properly labeled and that their benefits outweigh their risks.