Buspirone, an agonist of the serotonin receptor 5-HT1A, relaxes the proximal stomach to reduce symptoms of functional dyspepsia and increase gastric accommodation, according to trial results presented in the November issue of Clinical Gastroenterology and Hepatology.
Functional dyspepsia is a common gastrointestinal disorder. It is characterized by early satiation, postprandial fullness, and epigastric burning, along with upper abdominal bloating, belching and nausea.
It is believed to be caused partly by defects in gastric accommodation—the relaxation of the proximal stomach during meal ingestion to allow for an increase in gastric volume, without an increase in pressure—and hypersensitivity to gastric distension.
Jan Tack et al. investigated whether buspirone, which is used to treat anxiety but has also been shown to relax the proximal stomach, reduced symptoms of functional dyspepsia.
Seventeen people with functional dyspepsia were given buspirone or placebo, 3 times daily (before meals), for 4 weeks.
Tack et al. found that buspirone significantly reduced the overall severity of symptoms of dyspepsia, along with individual symptoms such as postprandial fullness, early satiation, and upper abdominal bloating, whereas the placebo did not (see below figure).
Buspirone did not alter the rate of gastric emptying of solids or sensitivity to gastric distention, but significantly increased gastric accommodation, compared with placebo.
The drug did not have any effects on epigastric pain or burning, indicating that it would be most effective for the functional dyspepsia subgroup with Postprandial Distress Syndrome, according to Rome III criteria.
The findings of Tack et al. agree with those from a previous study showing significant benefits from 4 weeks of treatment with the 5-HT1A agonist tandospirone.
How do 5-HT1A agonists work in the stomach? Drugs in this class have been shown to relax the proximal stomach through a nitrergic pathway. Because buspirone reduces rates of gastric emptying of liquids, and increases meal-induced gastric accommodation, Tack et al. propose that it reduces the tone of the proximal stomach. However, larger studies are needed to investigate its therapeutic mechanisms.
Read the article online.
Tack J, Janssen P, Masaoka T, et al. Efficacy of buspirone, a fundus-relaxing drug, in patients with functional dyspepsia. Clin Gastroenterol Hepatol 2012;10:1239-1245.