Background  Improvement in subjective symptoms has been reported in functional dyspepsia (FD) patients administered with acotiamide. Improvement was confirmed in meal‐related symptoms, such as postprandial fullness, upper abdominal bloating, and early satiety. We examined the mechanism underlying the effects of acotiamide on gastric accommodation reflex (GAR) and gastroduodenal motility in FD patients.

Methods  Thirty‐four FD patients (mean age, 40.4 years) were examined ultrasonographically before and after 14–18 days of acotiamide (100 mg t.i.d.) or placebo administration. To assess GAR, expansion rate in cross‐sectional area of the proximal stomach was measured after every 100‐mL ingestion, using a straw, of up to 400 mL of a liquid meal (consommé soup, 13.1 kcal; 400 mL) in a supine position. Next, we measured gastric emptying rate (GER), motility index (MI, antral contractions), and reflux index (RI, duodenogastric reflux) to assess gastroduodenal motility. Patients also completed a survey based on the seven‐point Likert scale both before and after drug administration.

Key Results  Of the 37 cases, 19 and 18 were administered with acotiamide and placebo A respectively, significant difference was observed in GAR between the acotiamide and placebo groups (21.7%vs 4.4%) after 400 mL ingestion. GER significantly accelerated after treatment in the acotiamide group (P = 0.012), no significant differences were observed in MI and RI between the two groups. Improvement rates were 35.3 and 11.8% for the acotiamide and placebo groups.

Conclusions & Inferences  Acotiamide significantly enhances GAR and GER in FD patients. Acotiamide may have therapeutic potential for FD patients.