Background and purpose: IV opioids and nonsteroidal anti-inflammatory drugs are commonly used to control pain in renal colic. Buprenorphine is a drug that is recently introduced for such cases. The aim of this study was to compare the effect of sublingual buprenorphine and intravenous morphine to control pain in acute renal colic.

Materials and methods: A randomized double-blind, placebo controlled clinical trial was performed in 203 patients with acute renal colic. The samples were divided into two groups to receive either 2 mg sublingual buprenorphine and 5cc IV distilled water (experimental group) or intravenous morphine 0.1 mg/kg and a sublingual placebo (control group). Pain reduction and drug side effects were compared between the two groups. Data analysis was conducted in SPSS ver.22 using repeated measures, Chi-square, and t-test. 

Results: The participants included 79 (38.9%) females and the mean age of the patients in experimental and control groups were 40.50±13.50 and 39.85±13.66, respectively (P=0.73). The mean time required for pain improvement after drug administration was 30.97±19.92 min in experimental group and 34.87±18.59 min in controls (P= 0.19). Significant decrease in pain severity was observed in both groups (P< 0.001) but the type of drug had no significant effect in reducing pain (P= 0.25). Side effects were similar in two groups except for itching that was significantly higher in patients receiving buprenorphine (P= 0.007).

Conclusion: The efficacy of buprenorphine in treatment of renal colic was found to be similar to that of intravenous morphine. Side effects were also similar in two groups except itching that was significantly more prevalent in experimental group.

(Clinical Trials Registry Number: IRCT2015082023696N1)