Effect of sumatriptan, a 5HT1 agonist, on the frequency of transient lower esophageal sphincter relaxations and gastroesophageal reflux in healthy subjects

OBJECTIVE: Meals increase the rate of transient lower esophageal sphincter (LES) relaxations, in part by gastric distension. The 5HT(1) agonist sumatriptan reduces fasting fundic tone, prolongs the meal-induced fundic relaxation, and delays gastric emptying. We therefore hypothesized that sumatriptan might have a significant effect on the rate of postprandial transient LES relaxations and gastroesophageal reflux. We aimed to study the effect of sumatriptan on postprandial transient LES relaxations and reflux in healthy subjects. METHODS: Esophageal manometry and pH monitoring were performed in 13 healthy volunteers for 30 min before and 90 min after a semiliquid meal (790 kcal). Sumatriptan 6 mg subcutaneous (s.c.) or s.c, placebo were administered on separate days 30 min after the meal. RESULTS: Sumatriptan significantly increased postprandial LES pressure from 11.0 +/- 1.2 mm Hg to 17.6 +/- 1.2 mm Hg (p < 0.05). However, reflux events were not diminished. In the contrary, reflux was more frequent after sumatriptan than after placebo (3 [1.5-4.5]/30 min res 2 [0-3]/30 min, p < 0.05). Transient LES relaxations were more frequent after sumatriptan, particularly in the second 30-min period after drug administration (3 [2.5-5]/30 min cs 2 [1.5-2]/30 min, p < 0.05). CONCLUSIONS: Sumatriptan prevents the natural decay in rate of transient LES relaxations that occurs after a meal and favors the occurrence of gastroesophageal reflux despite increasing LES pressure. The sustained postprandial high rate of transient LES relaxations after sumatriptan may be a consequence of a prolonged fundus relaxation and retention of meal in the proximal stomach. (C) 1999 by Am. Cell. of Gastroenterology.