These compounds, by virtue of their mode of action, were deemed to be as potent arthritis pain relievers as traditional non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen, but were believed to be safer than NSAIDs since they caused less gastrointestinal distress.

FORBES: Vioxx and Diclofenac: Why Are Two Heart Risky Pain Drugs Viewed Differently?