Effect of 4 x 250 mg erythromycin on human gastrointestinal transit

The motilin agonist erythromycin affects gastrointestinal motility. We studied its influence on gastric, intestinal, and colonic transit of indigestible solids. Ten healthy volunteers measured the gastrointestinal transit of a 6-8 mm metal sphere by metal detector with oral intake of 250 mg erythromycin q.i.d. or placebo in randomized order. Postprandial gastric emptying of the sphere after a standard meal was measured after a single i.v. dose of 250 mg erythromycin, subsequently followed by determination of small and large bowel transit. Motilin serum levels were measured for one hour. Gastric transit of the sphere was shortened from 243 +/- 34 to 72 +/- 46 min (mean +/- SD) (p = 0.002) and shifted from the interdigestive to the digestive phase. Small and large bowel transit were not influenced, and gastric transit times and motilin serum levels were not correlated. In conclusion, 250 mg erythromycin shortened postprandial gastric emptying of indigestible solids, most likely due to overcoming of pyloric sieving function by strong gastric antral contractions without effecting the transit through the lower part of the gastrointestinal tract.