Indomethacin as a postoperative analgesic for total hip arthroplasty

This prospective, randomized, double-blind trial evaluated the efficacy of rectal indomethacin as an adjunct to morphine for controlling postoperative pain. Fifty healthy patients undergoing elective hip arthroplasty were investigated. Group 1 (n = 25) received placebo suppositories, Group 2(n = 25) received indomethacin suppositories, 100 mg q8hr for five doses, starting at the end of the procedure. Both groups received morphine via a PCA pump, which recorded the amount of morphine delivered each hour. After a standardized general anaesthetic, PCA was begun in the recovery room. Pain was measured with a standard 100 mm VAS at 2, 6, 20, 28, 42 hr after surgery and the morphine consumption recorded. Over the 42-hr study period, patients in Group 2 required less morphine than those in Group 1 (34.8 +/- 21.8 mg vs 89.6 +/- 43.7, P less than 0.01). Pain scores were lower in Group 2 at 20, 28, 42 hr postoperatively. The incidence of side-effects did not differ between groups and no patient had excessive postoperative bleeding. The combination of indomethacin and morphine provided superior pain relief to morphine alone even though the control group had liberal access to morphine. This synergistic effect would make indomethacin a useful adjunct to intramuscular or epidural narcotics.