Effect of Oral Clarythromycin on Gall Bladder Motility in Subjects with Gall Stone Disease

Introduction: Motilin receptor stimulation has been shown to have a prokinetic effect on gall bladder motility in human beings (1). Clarythromycin is a semi-synthetic macrolide antibiotic widely used in clinical practice for various infections and H. Pylori eradication.

Aims & Methods: We aimed to find out whether oral clarythromycin has similar prokinetic activity to erythromycin on fasting and post-prandial human gall bladder in patients with gall stone disease.

Clarythromycin 500mg and a placebo were administered on two separate days least 72 hours apart to 10 subjects with gall stone disease. The medications were administered 8 hours before assessment of gall bladder volumes by ultrasonography (2). Gall bladder volumes were assessed in the fasting state and at 5-minute intervals for 50 minutes after a standard proprietary enteral feed (Ensure Plus 180ml, Abbott). Differences between the control and post clarythromycin scan volumes were tested with the Wilcoxon signed rank test, with p<0.05 taken as significant.

Results: Following administration of clarythromycin and placebo, gall bladder volumes were significantly different in the fasting state (15.7±2.3ml and 27.6±7.4ml, mean±SEM, p<0.05). Post-prandial volumes were significantly lower from 15 to 30 minutes after enteral feed in subjects following clarythromycin administration compared to placebo (10.2±1.4ml and 21.3±5.5ml, mean±SEM, p<0.05).

Conclusion: This study demonstrates that clarythromycin enhances both fasting and post-prandial gall bladder contraction in patients with gall stone disease. This action is similar to the prokinetic effect of erythromycin.