Relieving the Pain of Renal Colic

ABSTRACT & COMMENTARY

Source: Larkin GL, et al. Efficacy of ketorolac tromethamine versus meperidine in the ED treatment of acute renal colic. Am J Emerg Med 1999;17:6-10.

This study was a prospective, controlled, randomized, double-blind trial comparing the efficacy of intramuscular ketorolac and meperidine in the ED treatment of renal colic. Subjects were randomized to receive either 60 mg IM ketorolac or 100-150 mg IM meperidine, based on weight. Patients were excluded if a stone was not confirmed either by IVP or by the passage of a visible stone in the ED. Pain was measured on a 10 cm visual analogue scale at baseline 20, 40, 60, and 90-minute intervals. The three main outcome measures were: 1) the degree of pain relief; 2) the need for rescue medication; and 3) the time to discharge from the ED.

Of the 70 patients completing the trial, 33 received ketorolac and 37 received meperidine. Baseline pain scores were similar for both groups (pain scores ~8.00), as were demographic characteristics.

There was significantly greater pain relief reported in patients treated with ketorolac compared to meperidine at 40, 60, and 90 minutes (at 20 minutes there was no difference). The use of rescue medication was similar for both groups: 33% of ketorolac patients and 43% of meperidine patients required additional medication. While the number of patients discharged was not significantly different in the two groups, the time to discharge was significantly earlier in the ketorolac group (3.46 vs 4.33 hours), even when controlling for other factors. Side effects were minor and similar in both groups.

Comment by Stephanie B. Abbuhl, MD, FACEP

While this study had flaws in the design and data analysis, the effectiveness of ketorolac in renal colic should be the take-home message. These data favorably compare with what others have shown: that single-dose ketorolac is at least as good as, and is possibly better than, single-dose meperidine in the treatment of renal colic.1,2 Unfortunately, I am not aware of a good study comparing IV morphine to IV ketorolac.

It may be that a combined approach using both IV opiates and IV ketorolac is a rational one. These two classes of pain medication work differently, are dosed differently (single dose vs titration), and may complement each other. Studies with ketorolac and other NSAIDs suggest an important role for prostaglandin inhibition in the treatment of renal colic. It is thought that NSAIDs work through the relaxation of ureteral spasm and in the alleviation of renal capsular distention by diminishing renal blood flow and diuresis.

References

1. Oosterlinck W, et al. A double-blind, single dose comparison of intramuscular ketorolac tromethamine and pethidine in the treatment of renal colic. J Clin Parmacol 1990;30:336-341.

2. Cordell WH, et al. Comparison of intravenous ketorolac, meperidine, and both (balanaced analgesia) for renal colic. Ann Emerg Med 1996;28:151-158.