The Celecoxib Long-term Arthritis Safety Study (CLASS) evaluated the adverse gastrointestinal (GI) effects caused by the use of the selective cyclooxygenase 2 (COX-2) drug celecoxib and nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) in patients with osteoarthritis and rheumatoid arthritis.1 The study found no significant difference in the GI ulcer complication rate (ie, bleeding, perforation, or obstruction in the GI tract) between celecoxib and nonselective NSAIDs. The authors attributed this finding to a higher-than-anticipated aspirin comedication rate of 21% among study participants, a rate almost double that of previous clinical trial experience. Since usage patterns in clinical trials and routine clinical practice often differ, the purpose of the present study was to estimate aspirin comedication rates among long-term COX-2 users. To provide a thorough description of over-the-counter (OTC) NSAID and pain reliever use, we also examine comedication with 2 other OTC NSAIDs (ie, ibuprofen and naproxen sodium) and another commonly used OTC pain reliever, acetaminophen.
Cox ER, Frisse M, Behm A, Fairman KA. Over-the-Counter Pain Reliever and Aspirin Use Within a Sample of Long-term Cyclooxygenase 2 Users. Arch Intern Med. 2004;164(11):1243-1246. doi:10.1001/archinte.164.11.1243