Effects of erythromycin on gastric emptying, alcohol absorption and small intestinal transit in normal subjects

The effects of erythromycin on gastric emptying and intragastric distribution of a mixed solid/liquid meal, alcohol absorption and small intestinal transit were examined in eight male volunteers. Each subject received, in double-blind randomized order, either erythromycin as the lactobionate (3 mg.kg-1 i.v. over 20 min) or saline immediately before the consumption of a radioisotopically labeled test meal, which consisted of 330 g minced beef and 400 ml of orange juice containing ethanol (0.5 g.kg-1 body weight) and 10 g lactulose. Erythromycin increased the rate of total stomach emptying and proximal stomach emptying of both the solid and liquid components of the meal (p < 0.001), but slowed small intestinal transit (p < 0.01). Peak blood alcohol concentrations (p < 0.01) were higher after erythromycin, with a mean increase of 40%. There was a significant inverse relationship between peak blood alcohol concentrations and the 50% emptying time for the liquid component of the meal after saline (r = -0.70, p < 0.05), but not after erythromycin (r = -0.57, p < 0.1). The total area under the venous blood alcohol concentration time curve (i.e., total absorption) was greater (p < 0.01) after erythromycin. These results suggest that: faster emptying from the proximal stomach contributes to more rapid gastric emptying induced by erythromycin, erythromycin retards small intestinal transit and that erythromycin increases the total amount of alcohol absorbed as well as the rate of alcohol absorption. These latter effects are likely to reflect more rapid delivery of alcohol to the small intestine and reduced metabolism of alcohol by the gastric mucosa.