ATROPINE FOR THE TREATMENT OF BILIARY-TRACT PAIN - A DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL

Study objective: To compare the efficacy of IM atropine with placebo f or the treatment of pain caused by biliary tract disease. Design: Pros pective randomized, double-blind, crossover study. Setting: Emergency departments of a university medical center and affiliated county hospi tal. Participants: Fifty-five adults with biliary tract disease. Inter ventions: Subjects were randomized to receive either 0.6 mg (0.5 mL) I M atropine or normal saline placebo in a double-blinded manner. If pai n relief with the initial injection was inadequate, patients received the alternate injection. Pain was assessed by visual analog scale (0 t o 100 mm) before the initial injection and 30 to 40 minutes after each subsequent injection. Measurements and main results: Relief of pain w as complete after the initial injection in four of 28 (14%) who receiv ed atropine and four of 27 (15%) who received normal saline (P=.956). For subjects who received both injections, atropine and placebo result ed in similar pain relief (-12.0 mm versus -16.0 mm; P=.316). There al so was no difference in pain relief between atropine and placebo for t he subset of patients with biliary colic receiving both injections (-1 5.2 mm versus -17.0 mm; P=.658). This study had more than 80% power to detect a 7.5-mm difference in pain relief between atropine and placeb o in all patients with biliary tract disease and a 12.5-mm difference in those with biliary colic. Conclusion: Atropine is no better than pl acebo in the treatment of biliary tract pain.