Gastric emptying response to variable oral erythromycin dosing in diabetic gastroparesis

Intravenous erythromycin has been shown to improve gastric emptying in diabetic gastroparesis. Oral erythromycin also accelerates gastric emptying, but to a lesser degree. To determine if this is a dose-dependent phenomenon, gastric emptying was measured in 10 insulin-requiring diabetic patients with gastroparesis after administration of either 250 mg or 1000 mg of erythromycin or placebo. The drugs were orally administered in a randomized, double-blind fashion 30 min prior to ingestion of a meal containing [^99mTc]-sulfur colloid-labeled beef stew and [¹¹¹In]DTPA-labeled orange juice. Anterior and posterior gastric images were recorded for 3 hr at 15-min intervals using an externally positioned gamma camera. The results demonstrated that both doses of oral erythromycin significantly improved solid-phase gastric emptying. The mean half-emptying time of solids was decreased from 151±40 min with placebo to 58±10 min and 40±9 min with 250 mg and 1000 mg of erythromycin, respectively. However, a dose-dependent relationship was not demonstrated with the two doses of erythromycin employed. These results suggest that for most patients with diabetic gastroparesis, a single 250-mg dose of erythromycin will significantly improve gastric emptying. It is possible that a dose-dependent relationship will be demonstrated with doses of erythromycin less than 250 mg.