A 4-week randomized study of acetaminophen extended-release vs rofecoxib in knee osteoarthritis

To compare the safety and efficacy of acetaminophen extended-release (APAP ER) with rofecoxib for the management of pain associated with knee osteoarthritis (OA).

Four hundred and three adult patients with moderate pain secondary to knee OA were randomized to receive APAP ER 1300 mg three times daily, rofecoxib 12.5mg once daily, or rofecoxib 25mg once daily. Primary end point was change from baseline at week 4 in the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale score using a visual analog scale. This 4-week study was conducted at 23 US research sites from October 1999 to October 2000.

APAP ER was noninferior to rofecoxib 12.5mg because the upper 95% confidence limit (CL) for the least squares mean (LSM) change from baseline (35.27 mm at week 4) did not exceed the prespecified noninferiority limit of 50mm. The upper CL (57.39 mm) exceeded the noninferiority limit for APAP ER compared with rofecoxib 25mg at week 4. There were no significant differences among groups in the overall incidence of adverse events.

APAP ER 3900 mg daily was noninferior to rofecoxib 12.5mg daily, but noninferiority was not established to rofecoxib 25mg daily. APAP ER was well tolerated and no safety issues were identified. Based on the results of this study, APAP ER 3900 mg daily is an alternative to nonsteroidal anti-inflammatory drugs (NSAIDs), such as rofecoxib, in treating pain associated with knee OA.