Opioids, Ketorolac, and the Biliary Tract
Abstract & Commentary
Source: Barlas D, et al. Opioids prolong nuclear hepatobiliary imaging when given prior to scanning. J Emerg Med 2002;23:231-236.
It has been a maxim in emergency medicine that naturally occurring opiates such as morphine cause spasm of the sphincter of Oddi at the terminus of the common bile duct (CBD).1-6 In patients with biliary colic, spasm of the sphincter of Oddi can impair the flow of bile into the gastrointestinal tract and, in theory, prolong or intensify the colic episode. It is important to note that this never has been demonstrated to be a clinically relevant phenomenon. What is clinically relevant about the use of opiates, and especially morphine, is that they may delay tracer passage during nuclear hepatobiliary imaging (NHI) and mimic pathologic obstruction.
The authors sought to determine if opioid administration before NHI delays CBD visualization and prolongs imaging. One hundred ninety-eight cases of emergency department patients who underwent NHI were retrospectively reviewed (after excluding those with evidence for pathologic CBD obstruction). In this particular suburban, academic medical center, ultrasonography is available 24 hours a day, seven days a week, and emergency medicine ultrasound is performed based on emergency physician personal preference. The study was not designed to determine if there was a clinical effect of opioid use. Opioids were administered before NHI in 56 cases. The NHI delayed CBD visualization occurred in 28.6% of subjects who had received opioids and in 12.0% of those who had not (p < 0.01). Delayed imaging was performed in 77.8% of those who had received opioids and in 53.5% of those who had not (p < 0.01). The relative risk of delayed CBD visualization was 1.46 [95% CI 0.65-3.28] for meperidine, 4.18 [95% CI 2.00-8.82] for morphine, and 2.38 [95% CI 1.29-4.39] for any opioid. The authors conclude that opioids given before NHI are associated with delayed CBD visualization and more imaging sessions.
Source: Henderson SO, et al. Comparison of intravenous ketorolac and meperidine in the treatment of biliary colic. J Emerg Med 2002:23;237-241.
In this study, the authors compare the analgesic efficacy and tolerability of intravenous (IV) ketorolac with IV meperidine in the treatment of biliary colic. The study used prospective, randomized, double-blind methodology and employed a convenience sample of patients at a large inner-city facility during a two-year period. Patients randomly were assigned to receive ketorolac 30 mg IV or meperidine 50 mg IV. Pain was quantified using a four-point verbal rating system (VRS) as well as a visual analog scale (VAS). Patients were queried about their pain at times 0, 1/2 hour, one hour, and two hours after administration of the study medication, and adverse effects were recorded.
A total of 324 patients completed the study protocol, with 175 patients receiving ketorolac and 149 receiving meperidine. Patient demographics were similar for both groups, with mean age for the ketorolac group of 36.1 years and for the meperidine group of 34.6 years. No significant difference in pain control was found between ketorolac and meperidine in either the VAS or VRS for any time interval studied. The mean change in the VAS at time 2 h was 6.2 cm ± 3.6 cm for the ketorolac group, compared with 6.7 cm ± 3.6 cm for the meperidine group (p = 0.25). Patients receiving meperidine reported higher incidences of nausea and of dizziness than those receiving ketorolac (p = 0.009 and 0.003, respectively). The authors conclude that ketorolac is a well-tolerated, effective medication in the treatment of acute biliary colic. It showed similar efficacy to meperidine with a decreased number of adverse effects.
Commentary by Richard J. Hamilton, MD, FAAEM, ABMT
I find that I rarely use NHI to make this diagnosis. However, some of the consultant surgeons I work with do use these scans. Perhaps the avoidance of natural opioids is something that we can agree on, since there are so many semi-synthetic and synthetic opioids that can be used instead of morphine. However, my analgesic of choice is ketorolac, since I find that it provides pain relief without side effects, much like the results of the second study. One weakness of the second study, is that 50 mg of meperidine is a low dose—especially when compared to the 30 mg maximum dose of ketorolac. It is possible that higher doses of opioids would provide more rapid and complete pain relief, but I suspect that the incidence of adverse side effects would be higher.
Dr. Hamilton, Associate Professor of Emergency Medicine, Program Director, Emergency Medicine, MCP, Hahnemann University, Philadelphia, PA, is on the Editorial Board of Emergency Medicine Alert.
References
1. Dedrick DF, et al. Common bile duct pressure during enflurane anesthesia. Effects of morphine and subsequent naloxone. Arch Surg 1980;115:820-822.
2. Joehl RJ, et al. Opioid drugs cause bile duct obstruction during hepatobiliary scans. Am J Surg 1984;147:134-138.
3. Murphy P, et al. Narcotic anesthetic drugs: Their effect on biliary dynamics. Arch Surg 1980;115:710-711.
4. Pedersen SA, et al. The effects of morphine on biliary dynamics: A scintigraphic study with 99m Tc-HIDA. Scand J Gastroenterol 1987;22:982-986.
5. Radnay PA, et al. Common bile duct pressure changes after fentanyl, morphine, meperidine, butorphanol, and naloxone. Anesth Analg 1984;63:441-444.
6. Zsigmond ED, et al. Double-blind, placebo-controlled ultrasonographic confirmation of constriction of the common bile duct by morphine. Int J Clin Pharmacol Ther Toxicol 1993;3l:506-509.
The authors sought to determine if opioid administration before nuclear hepatobiliary imaging delays common bile duct visualization and prolongs imaging.
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