Background: Erythromycin has recently been found to be a gastrointestinal prokinetic agent in humans. Acute hyperglycaemia has been associated with delayed gastric emptying in both healthy controls and diabetic patients. Our aim was to investigate in gastroparetic patients (diabetics and idiopathics) whether hyperglycaemia, per se, reduces gastric motility during erythromycin-induced acceleration of gastric emptying of solids.
Methods: In 12 gastroparetic patients, 6 diabetics and 6 idiopathics, gastric emptying of solids was measured scintigraphically after giving placebo in normoglycaemia (5-8.9 mmol/l glucose) or 200 mg erythromycin lactobionate intravenously in normo- or hyperglycaemia (16-19 mmol/l glucose) induced by intravenous glucose infusion in random order on separate days.
Results: Erythromycin in normoglycaemia accelerated solids gastric emptying compared with placebo in all patients by abolishing the lag-phase duration and by decreasing the retained percentage of a meal in the stomach at 120 and 150 min (14.5% +/- 5.3% versus 88.4% +/- 10.6% and 3.5% +/- 2.1% versus 70.1% +/- 15.4%, respectively) (P < 0.001). The retained isotopic percentage in the stomach after erythromycin in induced hyperglycaemia compared with erythromycin in normoglycaemia, at 120 and 150 min, was increased (51.9% +/- 9.8% versus 14.5% +/- 5.3%, and 24.5% +/- 5.9% versus 3.5% +/- 2.1%, respectively) (P < 0.001) but was decreased in comparison with placebo (P < 0.001). A significantly increased percentage of isotope was retained in the stomach of the diabetic patients at 120 and 150 min, compared with the idiopathics, only after giving erythromycin in the hyperglycaemic condition (57.6% +/- 8.7% versus 46.1% +/- 7.6% (P = 0.036) and 27.8% +/- 5.7% versus 21.1 +/- 4.4% (P = 0.040), respectively).
Conclusions: Hyperglycaemia attenuates erythromycin-induced acceleration of solid-phase gastric emptying in idiopathic and diabetic gastroparesis and increases the retained isotopic meal in the stomach. Hyperglycaemia reduces gastric motility more in the diabetic patients with gastroparesis than in idiopathic patients.