Does intravenous ondansetron affect gastric emptying of a solid meal, gastric electrical activity or blood hormone levels in healthy volunteers?

Background: In previous studies, tropisetron has been shown to accelerate gastric emptying of a solid meal. However, it is uncertain whether other specific 5-hydroxytryptamine-3 receptor antagonists, such as ondansetron, also have a gastroprokinetic effect in humans.

Aim: To evaluate the effect of ondansetron on gastric half-emptying time (T1/2) of a solid meal, gastric myoelectrical activity and hormone levels in 14 healthy volunteers.

Methods: In a placebo-controlled, randomized, crossover study, we investigated the effects of ondansetron (8 mg intravenously) on the gastric emptying of solids (by scintigraphy), gastric myoelectrical activity (by electrogastrography) and the post-prandial release of cholecystokinin, gastrin, human pancreatic polypeptide, gastric inhibitory polypeptide, vasoactive intestinal polypeptide, motilin, substance P and galanin.

Results: The average T1/2 values were 86 min and 85.5 min without lag time (P=0.082) and 92 min and 93 min with lag time (P=0.158) for the placebo and ondansetron treatments, respectively. The average T1/2 of female volunteers was significantly longer than that of male volunteers. The dominant gastric electrical frequency and hormone plasma concentrations were not altered by ondansetron.

Conclusions: Ondansetron did not affect the gastric emptying of solids, the dominant gastric electrical frequency or the plasma concentrations of the analysed gastrointestinal peptides.