Diclofenac for pain after hip surgery.

Sixty-eight patients were studied during the day after hip replacement for arthrosis. No pain reliever was allowed within 4 h prior to initial assessment of pain. An injection of diclofenac 75 mg, pethidine 50 mg, or placebo was given intramuscularly, and a second injection was usually given after 3.5 h. Pain was recorded before and for 3 h after these injections. Ten patients in the placebo group demanded rescue drug because of insufficient pain relief. Four patients discontinued the study due to side effects: nausea (one patient in the placebo group) and somnolence or nausea (three patients in the pethidine group). Assessed both by visual analogue scale (VAS), and by the investigator's assessment, the diclofenac group had less pain than the pethidine and placebo groups. Side effects were least frequent in the diclofenac group. This study demonstrates that at the doses used here, compared with pethidine, diclofenac is more effective in relieving postoperative pain and has fewer side effects.