A combination of intravenous (IV) lidocaine and ketorolac was found to be superior to IV lidocaine alone and comparable with IV ketorolac alone for alleviating suspected renal colic pain in patients presenting to the emergency room (ER), according to a study published in the American Journal of Emergency Medicine.

Opioids and nonsteroidal anti-inflammatory drugs are often used to manage renal colic pain but are associated with adverse events (AEs). Lidocaine and ketorolac are thought to have synergistic effects.

In this randomized double-blind trial (Clinicaltrials.gov identifier: NCT02902770), a total of 150 patients age 18 to 64 who presented to the ER with complaints of acute flank, abdominal, or back pain were enrolled between November 2016 and October 2018. Pain intensity was assessed with an 11-point numeric rating scale (NRS). Study participants were treated in blinded fashion with IV lidocaine 1.5 mg/kg (mean age, 39.34; 54% men; baseline NRS, 8.36), IV ketorolac 30 mg (mean age, 42.34; 56% men; baseline NRS, 7.94) or a combination of IV lidocaine 1.5 mg/kg and IV ketorolac 30 mg (mean age, 43.92; 56% men; baseline NRS, 8.4; n=50 for each group). The study’s primary outcome was the difference in pain scores between groups 30 minutes post-administration. Secondary outcomes included comparative pain score reductions at 30 and 60 minutes, rescue analgesia (0.1 mg/kg IV morphine) requirements, and rates of AEs.

Mean pain score differences at 30 minutes were −2.89 (95% CI, −4.39 to −1.39) between participants receiving lidocaine alone vs lidocaine/ketorolac were: −0.92 (95% CI, −2.44 to 0.61) between ketorolac and the lidocaine/ketorolac combination; and −1.98 (95% CI, −3.69 to −0.27) between lidocaine and ketorolac. At 60 minutes, there remained statistically significant differences in mean pain scores in the groups that had received ketorolac vs lidocaine, as well as between groups  that had received lidocaine/ketorolac vs lidocaine alone.

Pain score reductions from baseline at 30 minutes were: 5.26 (95% CI, 4.52-6.00) for the ketorolac/lidocaine combination, 4.06 (95% CI, 3.23-4.89) for ketorolac alone, and 2.84 (95% CI, 2.23-3.44) for lidocaine alone. At 60 minutes, these reductions in mean pain scores were 6.24, 5.24, and 3.88, respectively.

Rescue analgesia requirements were similar across all groups. There were no clinically meaningful AEs or concerning vital sign changes in any of the participants. The 3 most common AEs were headache, nausea, and dizziness, mainly in patients treated with lidocaine alone.

Study limitations include the recruitment of participants from a single center, a possible selection bias, small sample size, strict exclusion criteria, and the short follow-up duration.

“[A]dministration of an IV lidocaine/ketorolac combination to ED patients with suspected or documented renal colic results in better analgesia in comparison to parenteral lidocaine alone but provides no analgesic advantages over parenteral ketorolac alone,” noted the authors.

Funding

This research was funded in part by an unrestricted grant from the New York State Department of Health Empire Clinical Research Investigator Program and by the Maimonides Research and Development Foundation.

Reference

Motov S, Fassassi C, Drapkin J, et al. Comparison of intravenous lidocaine/ketorolac combination to either analgesic alone for suspected renal colic pain in the ED. Am J Emerg Med. January 2019:1-8. doi:10.1016/j.ajem.2019.01.048

This article originally appeared on Clinical Pain Advisor