NSAIDs vs. Opiates for Pain in Acute Renal Colic
Are nonsteroidal anti-inflammatory drugs (NSAIDs) or opiates more effective for pain relief in patients with acute renal colic?
Data from randomized controlled trials comparing NSAIDs with opiates show that NSAIDs are associated with lower pain scores, less need for additional rescue medication, and less vomiting (particularly when compared with meperidine).
Acute renal colic is one of the most painful conditions and often is associated with nausea and vomiting. Holdgate and Pollock identified studies that compared NSAIDs with opiates in adults with acute renal colic (fewer than 12 hours duration) and moderate to severe pain. They found 20 studies that included a total of 1,613 patients and compared a total of five NSAIDs and five opiates (each study compared one opiate with one NSAID).
Study quality was mediocre; although most studies blinded either patients or outcome assessors during the study period, only five studies clearly concealed allocation at the start of the study, and only three definitely used intention-to-treat analysis. Data from the trials could not be combined statistically because of differences in methodology and wide variability in results.
Pain scores were reported in 13 studies. Ten studies found that patients who took NSAIDs had lower pain scores; two studies found no difference, and one study reported lower pain scores in patients who took opiates. There was no difference between treatment groups in complete pain relief at 30 or 60 minutes. Additional “rescue” analgesia was needed more often in patients randomized to opiates (25.4 versus 18.9 percent; P = .007; number needed to treat, 15). Vomiting was more common in patients randomized to opiates (19.5 versus 5.8 percent; P < .00001; number needed to harm, seven). Meperidine caused more vomiting than other opiates; there was no difference in the risk of vomiting between other opiates and NSAIDs.
The Institute for Clinical Systems Improvement's guideline on acute pain management suggests that NSAIDS are often adequate for mild or moderate pain.1) It recommends that opioids be added to pain therapy in these patients only if pain is not controlled adequately with NSAIDs alone.