Erythromycin has been found to be a gastrointestinal prokinetic agent of hy
pertonic liquids, while acute hyperglycemia has been associated with delaye
d gastric emptying in diabetic patients. Aim: To investigate whether hyperg
lycemia, per se, reduces gastric motility during erythromycin-induced accel
eration on gastric emptying of hypertonic liquids in diabetic patients. Met
hods: In 12 type-I diabetic patients following a hypertonic radiolabeled li
quid meal, gastric emptying was measured scintigraphically during normoglyc
emia (5-8.9 mmol/l glucose) or hyperglycemia induced by intravenous (16-19
mmol/l) glucose infusion. The tests were performed on 4 separate days in ra
ndom order after administering either placebo or 200 mg i.v. erythromycin.
Results: In the hyperglycemic state compared to normoglycemia, the gastric
emptying of the hypertonic liquid was reduced after placebo or erythromycin
administration. The lag-phase duration (17.8+/-5.5 and 7.8+/-4.5 vs. 10.8/-3.4 and 3.7+/-2.5 min, respectively, p<0.001), the overall gastric emptyi
ng time of the half meal (52.8+/-13 and 24.9+/-5.5 vs. 42.5+/-10.5 min and
16.6+/-6 min, respectively, p<0.001) and the retained percentage of liquid
meal in the stomach at 60 and 100 min postprandially(p < 0.001) were signif
icantly increased. Conclusions: The erythromycin-induced acceleration on ga
stric emptying of hypertonic liquids in diabetic patients is related to the
plasma glucose level. The induced hyperglycemia reduces the erythromycin-i
nduced acceleration of liquid-phase gastric emptying, decreasing the overal
l gastric emptying rate. In spite of the inhibitory effect of induced hyper
glycemia on the gastric emptying of hypertonic liquids, erythromycin is sti
ll able to accelerate the emptying rate and could prove to be a useful prok
inetic agent under hyperglycemic conditions. Copyright (C) 2000 S. Karger A
G, Basel.