Results of a six-month study comparing the safety and efficacy of nabumetone and aspirin in the treatment of osteoarthritis.

The safety and efficacy of nabumetone (1,000 mg at bedtime) were compared with those of aspirin (900 mg four times daily) in the treatment of osteoarthritis in adult patients in a private practice setting as part of a six-month, double-blind, controlled, randomized, parallel group study. At screening, baseline, and Days 7, 14, 28, 56, 112, and 168, efficacy was evaluated according to independent assessments by the patients and the physician of overall osteoarthritic activity and pain and by the physician's assessment with respect to a defined activity. Of the 40 patients enrolled, 37 were evaluable for efficacy (19 in the nabumetone group and 18 in the aspirin group). Demographic parameters and diagnostic criteria for osteoarthritis were comparable between the groups, although there was a preponderance of women in the nabumetone group. Significant improvement from baseline in all five efficacy parameters was observed in both groups. Safety was evaluated for all 20 enrolled patients in each group. The percentage of aspirin-treated patients who withdrew from the study due to adverse experiences was greater (60 percent versus 20 percent), as was the number with at least one treatment-related adverse experience (19, or 95 percent, versus 11, or 55 percent). Treatment-related adverse experiences described as moderate or severe were reported by 70 percent of the aspirin-treated patients and by 35 percent of the nabumetone-treated patients. In this study, nabumetone 1,000 mg at bedtime had an acceptable safety profile and was as effective as aspirin 900 mg four times daily in the treatment of osteoarthritis.