Double-blind comparison of butorphanol and nalbuphine on the common bile duct by ultrasonography in man.

Butorphanol and nalbuphine, narcotic agonist-antagonists were shown to cause no increase in biliary pressure in contrast to morphine in dogs or men. A non-invasive, ultrasonographic technique confirmed that morphine caused constriction of the common bile duct while placebo caused no effect. To prove the lack of constrictive effect of butorphanol and nalbuphine on the common bile duct, the changes in its diameter were measured following placebo or the two agonist-antagonists by ultrasonography. In a double-blind, randomized study, 17 patients undergoing open cholecystectomy were evaluated. No morphine or opioids were allowed for 12 hours prior to the study. After premedication with midazolam and glycopyrrolate, anesthesia was induced by midazolam, 50 micrograms.kg-1 and thiopental, 3.0-5.0 mg.kg-1. Tracheal intubation was facilitated by succinylcholine 1.0 mg.kg-1 and muscle relaxation was maintained with vecuronium. Anesthesia was maintained with isoflurane or enflurane and nitrous oxide in oxygen. After imaging the common bile duct by ultrasonography, placebo, nalbuphine 0.3 mg.kg-1 or butorphanol 40 micrograms.kg-1 were injected intravenously. The diameter of the common bile duct was measured before and at 4 and 8 minutes after drug administration. One-way analysis of variance and paired t-test were utilized for statistical analysis. P < 0.05 was considered significant. No significant changes in the common bile duct diameter was observed after placebo administration, nor was any change observed after either nalbuphine or butorphanol as compared to the baseline. The comparison of three groups of patients showed no statistically significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)