Promethazine paten?

Promethazine is a first‑generation, non‑selective antihistamine that was first synthesized in the late 1950s and introduced to the market in the early 1960s. Because it has been on the market for more than six decades, all of the original patents that covered its discovery, synthesis, and primary therapeutic indications have long since expired. Here’s a quick rundown of the patent landscape for Promethazine:

What does “patent expired” mean for Promethazine?

• Generic Availability: Because all foundational patents have lapsed, generic manufacturers can produce and sell promethazine under the name “promethazine hydrochloride” (the common salt form used in most oral solutions and tablets).
• Formulation Patents: Some newer formulation patents (e.g., a once‑daily extended‑release formulation or a pediatric oral suspension with a proprietary taste‑masking excipient) may still be in force in particular markets. Those patents only restrict the specific formulation, not the core drug substance itself.
• Combination Patents: If a new therapeutic use involves a combination of promethazine with another drug (e.g., a cough suppressant plus a decongestant), a combination patent could still be in play, but the core antihistamine remains free for generic use.

Where to look if you need the detailed patent history

Quick FAQ

Bottom line:
Promethazine as a drug compound is in the public domain; its original patents have long expired. Current patent activity mainly revolves around novel formulations or specific therapeutic indications rather than the core antihistamine itself. If you’re looking into a particular formulation or a new indication, check the USPTO or EPO databases with the specific details you need.