Cox-2 Inhibitors (cont.)

The other cyclooxygenase, COX-2, also produces prostaglandins, but the COX-2 enzyme is located specifically in areas of the body that commonly are involved in inflammation but not in the stomach. When the COX-2 enzyme is blocked, inflammation is reduced; however, since the COX-2 enzyme does not play a role in protecting the stomach or intestine, COX-2 specific NSAIDs do not have the same risk of injuring the stomach or intestines.

Older NSAIDs (for example, aspirin, ibuprofen, naproxen, etc.) all act by blocking the action of both the COX-1 and COX-2 enzymes. COX-2 inhibitors selectively block the COX-2 enzyme and therefore have a lower risk of causing ulcers of the stomach or intestine.

What are side effects of COX-2 inhibitors?

Common side effects of COX-2 inhibitors include:

COX-2 inhibitors may increase the risk of serious, even fatal stomach and intestinal adverse reactions, such as ulcers, bleeding, and perforation of the stomach or intestines but to a lesser extent than other nonselective NSAIDs that block both COX-1 and COX-2. These events can occur at any time during treatment and without warning symptoms.

People allergic to sulfonamides, for example, trimethoprim (Trimpex, Proloprim, Primsol) and sulfamethoxazole (Bactrim), aspirin or other NSAIDs may experience allergic reactions to COX-2 inhibitors and should not take them.

NSAIDs, including COX-2 inhibitors, may increase the risk of heart attacks, stroke, and related conditions. This risk may increase in patients with risk factors for heart disease and related conditions and with longer duration of use. NSAIDs should not be used after coronary artery bypass graft (CABG) surgery.

Which COX-2 inhibitors are available in the United States?

Celecoxib (Celebrex) is the only COX-2 inhibitor available in the United States. Rofecoxib (Vioxx) and valdecoxib (Bextra) were withdrawn from the market in 2004 and 2005, respectively, because they excessively increased the risk of heart attacks and strokes with long term use.

Reference: FDA Prescribing Information


Last Editorial Review: 7/22/2009



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