- Cyclooxygenase-2 (Cox-2) inhibitor
- A class of drugs that selectively blocks a specific enzyme called Cox-2. Blocking this enzyme impedes the production of the chemical messengers that cause the pain and swelling of arthritis inflammation. Cyclooxygenase-1 (Cox-1) is an enzyme which is normally present in a variety of areas of the body, including sites of inflammation and the stomach. The Cox-1 enzyme in the stomach produces certain chemical messengers (called prostaglandins) that ensure the natural mucus lining which protects the stomach. Common anti-inflammatory drugs like aspirin block the function of the Cox-1 enzyme along with another enzyme, Cox- 2 (see below). When the Cox-1 enzyme is blocked, inflammation is reduced, but the protective mucus lining of the stomach is also reduced, which can cause stomach upset, ulceration, and bleeding from the stomach and intestines. Cox-2 also produces these chemical messenger molecules, but the Cox-2 enzyme is located specifically in areas of the body that are responsible for inflammation and not in the stomach. When the Cox-2 enzyme is blocked, inflammation is reduced. Since the Cox-2 enzyme does not play a role in the normal function of the stomach or intestinal tract, medications which selectively block Cox-2 do not present the risk of injuring the stomach or intestines. Newly developed drugs that selectively block the Cox-2 enzyme are called Cox-2 inhibitors. Blocking this enzyme impedes the production of the prostaglandins that cause the pain and swelling of arthritis inflammation. The common anti-inflammatory drugs (like aspirin, ibuprofen, and naproxen) all act by blocking the action of both the Cox-1 and Cox-2 enzymes. The Cox-2 inhibitors represent a new class of drugs that do not affect Cox-1, but selectively block only Cox-2. This selective action provides the benefits of reducing inflammation without irritating the stomach. These drugs pose a significant advantage in comparison to previous anti-inflammatory drugs in that they carry nowhere near the risk of stomach ulceration and bleeding. The Cox-2 inhibitors are now on the market in the form of celeCoxib (Celebrex) and rofeCoxib (Vioxx). It is widely expected that Cox-2 inhibitors will be of great value to people with arthritis. (The Cox-2 inhibitors have also been called
Medical dictionary. 2011.