A double-blind, placebo controlled comparison of the morphine sparing effect of oral rofecoxib and diclofenac for acute renal colic

PURPOSE: We compared the morphine sparing effect of a single dose of 50 mg oral rofecoxib, 3, 8-hourly doses of 50 mg diclofenac and placebo for acute renal colic. MATERIALS AND METHODS: Patients who were 18 to 69 years old with clinically diagnosed acute renal colic and a visual analog scale (VAS) score of 40 mm or greater at hospital admission were randomized to receive 1 of the 3 treatment regimens, delivered in 3 identical encapsulated tablets. The primary end point was the mean total amount of intravenously administered morphine in the 24 hours following study medication dose 1. Secondary end points were mean VAS score and the number of treatment withdrawals due to pain. RESULTS: Of 400 patients admitted with acute flank pain 225 fulfilled the inclusion criteria, of whom 110 (49%) were eligible for evaluation and received rofecoxib (36), diclofenac (39) and placebo (35). Baseline characteristics in the 3 groups did not differ. Intent to treat analysis showed that mean morphine consumption was 13.6 mg in the rofecoxib group (95% CI 10.3 to 16.9), 10.2 mg in the diclofenac group (95% CI 7.7 to 12.7) and 11.5 mg in the placebo group (95% CI 8.8 to 14.3). The differences were not significant (p = 0.23). The same applied to mean VAS scores in the 3 groups (p = 0.22). There were no differences in the number of pain related treatment withdrawals (p = 0.64). CONCLUSIONS: No clinically relevant morphine sparing effect was seen in patients with renal colic treated with 50 mg oral diclofenac every 8 hours or a single dose of 50 mg rofecoxib as a representative of the specific inhibitors of cyclooxygenase-2.