Intravenous azithromycin is a viable substitute for erythromycin to cleanse the visual field during endoscopic treatment of gastrointestinal bleeding, and it also may have a few advantages, researchers have found.

Although IV erythromycin is an effective gastric lavage for improving the endoscopic treatment of GI bleeding, preparing the solution is time-consuming—taking roughly an hour, compared with about five minutes for IV azithromycin, said Danny Issa, MD, a GI fellow at the Virginia Commonwealth University School of Medicine, in Richmond, who helped conduct the new study.

“The difference in preparation time could be clinically relevant because of the potential for delays to endoscopy in urgent cases,” Dr. Issa said. Presenting data at the 2017 meeting of the World Congress of Gastroenterology/American College of Gastroenterology comparing these agents (abstract 31), he also noted that a substitute for IV erythromycin may be useful because of reported shortages of the antibiotic in some areas of the country.

Dr. Issa and his colleagues frequently use azithromycin in place of erythromycin in patients undergoing endoscopic treatment of GI bleeding. The new study was a retrospective comparison of these two antibiotics, with the primary outcome of quality of visualization as assessed by two experienced gastroenterologists blinded to the infusion agent.

The independent observers rated endoscopic recordings on an 8-point scale. Based on ease of visualization, up to 2 points each were assigned to the fundus, body, antrum and bulb. The researchers also assessed a variety of secondary end points, including duration of the procedure.

Although a higher proportion of the patients receiving erythromycin (n=50) had cirrhosis than those who received azithromycin (n=26), other characteristics, such as mean age and sex, were similar.

On the 8-point scale, with 8 representing the best rating, azithromycin was associated with a median score of 7.0, which was significantly better than the score of 6.0 associated with erythromycin, according to Dr. Issa. The time to administration was shorter for azithromycin, but this difference did not reach statistical significance (48.5 vs. 67 minutes; P=0.92). The shorter length of stay in patients receiving azithromycin also did not reach statistical significance (6.0 vs. 7.0 days; P=0.48). The researchers did not observe any significant differences in other outcomes they evaluated, including the need for repeat endoscopies or the number of units of blood transfused.

The study shows that azithromycin is at least equivalent to erythromycin for improving visualization in patients with upper GI bleeding, but Dr. Issa indicated that better visualization and the potential for an earlier time to endoscopy might improve outcomes. He recommended a larger randomized trial to compare these approaches.

Although the study was small and retrospective, John R. Saltzman, MD, director of endoscopy at Brigham and Women’s Hospital, in Boston, agreed that a larger trial of the two antibiotics is warranted. He cited a previous study that associated azithromycin with similar gastric prokinetic properties (Br J Pharmacol 2013;168:1859-1867).

“Erythromycin, with its prokinetic motilin receptor agonist properties, has been shown to improve gastric visualization, but it is not always readily available, requires reconstitution and requires infusion over 20 to 60 minutes,” Dr. Saltzman said. Despite azithromycin’s similar properties and potential for use as a substitute, it “has not been previously studied in patients with GI bleeding.”

—Ted Bosworth

Drs. Issa and Saltzman reported no relevant financial conflicts of interest.