EFFECT OF ORAL ERYTHROMYCIN ON GALLBLADDER MOTILITY IN NORMAL SUBJECTS AND SUBJECTS WITH GALLSTONES

The action of the motilin receptor agonist erythromycin on human gallbladder contraction, measured by ultrasound, both in normal subjects and those with gallstone disease was studied. In 17 normal subjects, oral erythromycin administration (500 mg; vs. placebo) reduced fasting gallbladder volume at 2 hours (26.2 vs. 19.0 mL; P < 0.001), and postprandial residual gallbladder volume (9.0 vs. 4.4 mL; P < 0.001) and the rate constant of gallbladder emptying following the meal was significantly increased. Erythromycin also reduced fasting and residual gallbladder volumes in 13 patients with gallstone disease: in 6 who underwent cholecystolithotomy, fasting volume was 29.5 vs. 22.3 mL (P < 0.05) and residual volume was 17.7 vs. 6.5 mL (P < 0.05), and in 7 with gallstones in situ, fasting volume was 23.8 vs. 14.3 mL (P < 0.05) and residual volume was 17.2 vs. 5.0 mL (P < 0.05). In 7 of 8 subjects with gallstones and impaired gallbladder emptying, the gallbladder emptied normally following administration of erythromycin, and in 3 of the other 5 gallstone subjects gallbladder emptying was increased. In 6 normal subjects given erythromycin three times weekly for 1 month, the effect was maintained (fasting volume, 18.8 mL, P < 0.001; residual volume, 3.7 mL, P < 0.001). Oral erythromycin significantly reduces fasting and postprandial residual gallbladder volumes in both normal subjects and subjects with gallstones and reverses the gallbladder motility defect found in a proportion of subjects with gallstones. This effect is maintained for a month in normal subjects. © 1992.