Objective: To compare the analgesic efficacy and safety of nonprescription doses of naproxen sodium, ibuprofen, and placebo in patients with osteoarthritis (OA) of the knee.
Methods: In 2 identical multicenter, randomized, double-blind, placebo-controlled, multidose, parallel-design studies, patients aged > or = 25 years with OA were randomized to daily doses of naproxen sodium 660 mg, naproxen sodium 440 mg (patients > or = 65 years), ibuprofen 1200 mg, or placebo, for 7 days.
Results: For investigator and patient assessment of knee joint pain, naproxen sodium (440/660 mg) and ibuprofen were clinically effective at relieving pain compared with placebo (n = 444); both treatments reduced the mean symptom score by 30-45%, compared with a 20-25% reduction with placebo. Naproxen sodium (440/660 mg) significantly improved all 7 symptoms from baseline compared with placebo, while ibuprofen significantly improved 5 of the symptoms. For the subgroup of patients aged > or = 65 years (n = 183), naproxen sodium 440 mg was significantly superior to placebo in all symptoms except pain on weight-bearing; ibuprofen only significantly reduced day pain. For daily diary evaluations, naproxen sodium and ibuprofen were effective in reducing all 6 symptoms; there was a trend toward higher efficacy for night-time pain with naproxen sodium 440/660 mg compared with ibuprofen. There were no significant differences in adverse event reporting between groups.
Conclusion: Over-the-counter doses of naproxen sodium (440/660 mg) and ibuprofen (1200 mg) effectively relieve pain in patients with mild to moderate OA of the knee. Naproxen sodium provided more effective pain relief for most variables compared with placebo, and for night pain compared with ibuprofen. Efficacy was combined with good safety and tolerability.