What term describes a drug that is usually sold under a patented or trade name?

The term that describes a drug usually sold under a patented or trade name is proprietary drug. Proprietary drugs are developed and marketed by a specific manufacturer who holds the patent on the formulation and is thus able to brand and sell it under a unique name. This designation signifies that the drug's recipe is protected by intellectual property rights, preventing other manufacturers from producing an identical product. As a result, proprietary drugs are often associated with significant investment in marketing and development, making them easily recognizable but typically more expensive than their generic counterparts.

This term contrasts with generic drugs, which contain the same active ingredients as their branded counterparts but are sold under their chemical name without patent protection, and over-the-counter (OTC) drugs, which can be purchased without a prescription. Prescription drugs can include both proprietary and generic types but don't specifically highlight the branding and patent aspect as effectively as proprietary does.