Golden HE, Moskowitz RW, Minic M.
American Journal of Therapeutics 2004;11:85-94.

In two identical multi-centre, randomized, double-blind, placebo-controlled, multi-dose, parallel-design studies, nonprescription doses of naproxen sodium, acetaminophen and placebo were compared to determine their efficacy and safety in osteoarthritis of the knee. Patients with osteoarthritis aged 60.6 +/- 12.8 years were randomized to daily doses of the following, for seven days:

• 660 mg naproxen sodium (patients = 65 years received 440 mg naproxen sodium)
• 4,000 mg acetaminophen
• placebo.

The results conclude that naproxen sodium provided significantly greater improvements for pain in the following:

• at rest
• on passive motion
• on weight-bearing
• stiffness after rest (morning)
• day and night pain compared with placebo.

It also found significantly greater relief from resting pain than acetaminophen (p< 0.05). Acetaminophen provided significantly greater improvements in day pain compared with placebo. Daily evaluations showed naproxen sodium (440/660 mg) provided superior pain relief to acetaminophen and was significantly better than acetaminophen at reducing difficulties experienced in walking several blocks and difficulties in bending, lifting and stooping. Naproxen sodium (440/660 mg) and acetaminophen (4,000 mg) were significantly more effective than placebo in improving mobility level, household tasks, and walking and bending.

No differences were observed between active treatments although patient and investigator evaluation scores were significantly higher in naproxen sodium and acetaminophen groups compared with placebo. Additionally, naproxen sodium and acetaminophen had similar safety profiles to placebo. Nonprescription doses of naproxen sodium relieved pain and other osteoarthritis symptoms. The authors conclude that naproxen sodium is an alternative in the initial treatment of osteoarthritis that may be preferred to acetaminophen as first-line therapy in patients with moderate or severe pain.