Erythromycin enhances solid-phase gastric emptying in induced-hyperglycemia in patients with truncal vagotomy and pyloroplasty

Erythromycin has been found to be a gastrointestinal prokinetic agent while acute hyperglycemia has been associated with delayed gastric emptying in h ealthy controls and diabetics. The aim of this study was to investigate whe ther hyperglycemia, per se, alters gastric motility, during erythromycin-in duced acceleration of gastric emptying of solids in patients with truncal v agotomy and pyloroplasty (TVP) and the role of vagus nerves. Eight TVP pati ents and sh controls underwent scintigraphic measurement of gastric emptyin g of a solid meal, during placebo in normoglycemia (5-8.9 mmol/liter glucos e) or 200 mg intravenous erythromycin lactobionate in normo- or hyperglycem ia (16-19 mmol/liter glucose) induced by intravenous glucose infusion, on s eparate days in random order. In the TW patients during normoglycemia, the erythromycin compared to placebo accelerated the meal gastric half-emptying time (T 1/2), (37.12 +/- 6.87 vs 91.88 +/- 11.53, P < 0.001) and decreased the lag-phase duration (P < 0.001) and the percentage of meal retained in the stomach at 120 min (P < 0.001), Erythromycin in hyperglycemia compared to normoglycemia increased T 1/2 (61.25 +/- 10.67 vs 37.12 +/- 6.87, P < 0. 001), prolonged lag-phase duration (P ( 0.001), and the percentage of isoto pe retained in the stomach at 120 min (P < 0.001). The T 1/2, the lag phase duration, and the meal retained in the stomach at 120 min, after giving pl acebo was significantly increased, compared to erythromycin administration in hyperglycemia (P < 0.001), Significant differences among patients and co ntrols were found during gastric emptying after giving placebo and after er ythromycin in hyperglycemia (P = 0.04 and P = 0.007, respectively), while n onsignificant differences were found after giving erythromycin in normoglyc emia. We conclude that the effect of erythromycin-induced acceleration on g astric emptying is related to the plasma glucose level. Hyperglycemia reduc es the erythromycin-induced acceleration of gastric emptying of solids in b oth controls and TVP patients. A significant increase in the delay of gastr ic emptying was achieved in TVP patients compared to controls after giving erythromycin in hyperglycemia and after placebo, Despite the inhibitory eff ect of induced hyperglycemia on gastric emptying, erythromycin is still abl e to accelerate the emptying rate and could prove to be a useful prokinetic agent under hyperglycemic conditions, Hyperglycemia may indicate a choline rgic-antagonist pathway that delays the erythromycin-induced acceleration o f gastric emptying of solids and is more evident in vagotomized patients th an controls, who retain the functional integrity of the vagus nerves.