Numerous European clinical trials begun more than 12 years ago have clearly demonstrated flurbiprofen's safety and efficacy as an analgesic, anti-inflammatory, and antipyretic agent. In preclinical studies, flurbiprofen was at least as potent as indomethacin, and approximately 200 times more potent than aspirin. For patients with rheumatoid arthritis, a review of several trials found flurbiprofen often superior to aspirin and naproxen, and equivalent to indomethacin and ibuprofen in efficacy. Acetaminophen appeared no more effective than placebo for patients with rheumatoid arthritis. For patients with ankylosing spondylitis, flurbiprofen was also shown to be equivalent or superior to indomethacin and phenylbutazone. For patients with osteoarthritis of the peripheral joints, spine, hip, and knee, flurbiprofen was again found equal to ibuprofen, diclofenac, indomethacin, and naproxen. Side effects with flurbiprofen were few and predominantly related to the gastrointestinal tract.