Monitoring esophageal transit of wax-polished alendronate in healthy postmenopausal women: A new technique for the study of pill transit time

Abstract

Background: Alendronate sodium is an oral nitrogen-containing bisphosphonate that has been proven effective in the prevention and treatment of osteoporosis. Although adverse events are no more common with alendronate than with placebo in clinical trials, there have been postmarketing case reports of esophagitis and esophageal erosions in alendronate-treated patients. Delay in the transit of the tablet through the esophagus may contribute to the development of upper gastrointestinal (GI) symptoms, but few published techniques exist for the study of esophageal pill transit. Objective: The purpose of this pilot study was to describe a novel method to investigate the esophageal transit time of pills, using alendronate as a model. Methods: A total of 30 bisphosphonate-naive, healthy postmenopausal women were administered alendronate 10-mg, oval wax-polished tablets labeled with technetium Tc 99m pertechnetate. Simultaneous emission/transmission images were acquired at 1 second per frame. Two measures of esophageal transit time were calculated from the images: time to pass below the diaphragm and time-activity curves in a region of interest (ROI) drawn over the esophagus. Results: Median transit time from oropharynx to below the diaphragm was 3 seconds (range, 2–6 seconds). Using the ROI technique, median transit time for the whole esophagus was 5 seconds (range, 2–17 seconds). In 25 of 30 subjects (83%), esophageal transit time was ≤6 seconds. In the 5 subjects in whom transit time was ≥6 seconds, virtually all of this time was in the distal third of the esophagus; transit through the proximal two thirds was ≤3 seconds in all 30 subjects. Conclusions: As measured by this technique, oval wax-polished alendronate tablets pass through the esophagus rapidly. This technique could be used to investigate the effect of tablet shape or coating on esophageal transit as well as changes in dosing regimens for patients with normal or abnormal upper GI anatomy.