Comparative analgesic effects of naproxen sodium, aspirin, and placebo.

The analgesic efficacy of a single 550-mg dose of naproxen sodium was compared with that of 650 mg aspirin and a placebo in a double-blind, parallel trial. The study was carried out in an industrial setting and included 201 adult patients with various acute pain states. Musculoskeletal pain was the most common type of pain treated. Pain intensity differences and patients' evaluation of pain relief indicated statistically significantly earlier and better analgesia with naproxen sodium than with both aspirin and placebo. The summed pain intensity differences (SPID) showed that naproxen sodium performed better than aspirin, which in turn did better than placebo. the difference between naproxen sodium and aspirin means for SPID was numerically equal to the difference between the aspirin and placebo means for SPID. Further, the incidence of side effects was less with naproxen sodium than with aspirin. The study demonstrated that naproxen sodium provided earlier and better pain relief than aspirin, that this effect was consistent over time, and that the incidence of side effects associated with naproxen sodium was less than with aspirin.