Effect of the 5-HT3 receptor antagonist, ondansetron, on gastric size in dyspeptic patients with impaired gastric accommodation

Background. A reduction of gastric accommodation after a meal has been documented in patients with idiopathic dyspepsia. In these patients the administration of a 5-HT3 receptor antagonist may reduce some of the dyspeptic symptoms; it is not clear however, whether these drugs influence gastric adaptation to distension as well. Aim. To evaluate the effects of the 5-HT3 receptor antagonist, ondansetron, on gastric distension after a liquid meal in dyspeptic patients with reduced gastric accommodation. Methods. Before and after a 500 ml water load, gastric accommodation (area of the proximal and distal stomach) was evaluated using real-time ultrasonography in 21 idiopathic dyspepsia patients and 26 healthy controls. In dyspeptic patients, the test was repeated twice: after the administration of placebo and after ondansetron 8 mg i.v. (in both cases, 15 min prior to the water load). Secondary outcomes were epigastric pain, fullness and nausea as assessed by a visual analogue scale at basal and after ondansetron. Results. Fasting gastric size was similar in dyspeptic and controls. Compared with controls, dyspeptic patients showed a statistically significant smaller area of the proximal stomach (14.7 +/- 1.2 cm(2) vs. 18.6 +/- 1.4 cm(2), respectively; p = 0.0247). In dyspeptic patients, gastric proximal and distal size did not change significantly following placebo, whereas after the administration of ondansetron the mean area of the proximal and distal stomach significantly increased (proximal stomach: 14.6 +/- 1.6 cm(2) placebo, 20.4 +/- 1.9 cm(2) ondansetron, p = 0.0095; distal stomach: 8.9 +/- 0.9 placebo, 11.4 +/- 1.2 cm(2) ondansetron, p = 0.0409). Of the symptoms, only nausea was significantly reduced after ondansetron. Conclusion. In dyspeptic patients with impaired gastric accommodation, ondansetron reverts gastric accommodation to within the range of controls. (c) 2007 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.