Naproxen and aspirin in acute musculoskeletal disorders: a double-blind, parallel study in patients with sports injuries.

Seventy-nine patients with injuries of less than 14-days' duration were treated with either 750 mg naproxen or 2 g acetylsalicylic acid daily for 7 days in a double-blind trial. A statistically significant improvement (p less than 0.001) was noted in both treatment groups in respect of tenderness on palpation, pain on movement and functional capacity. However, there were no significant differences between the groups. Fresh injuries were over-represented in the acetylsalicylic acid group (p less than 0.01), and when all patients were analyzed together, a significantly better treatment result was obtained the shorter the interval between injury and start of treatment. This might have influenced the results from this study. Fifteen side-effects were reported by 11 patients, 5 in the naproxen group and 6 in the acetylsalicylic acid group. None was serious, and only 2 patients interrupted the treatment for this reason. It is suggested that treatment with analgesics or anti-inflammatory drugs should start as early as possible after the injury.