Effect of an oral beta2-adrenergic agonist on lower esophageal sphincter pressure in normals and in patients with achalasia.

The effect of the beta2-adrenergic agonist, carbuterol, was studied on the lower esophageal sphincter (LES) pressure in normals and in patients with achalasia. In normals, the mean LES pressure decreased from 23.1 +/- 6.2 mm Hg (mean +/- SEM) to 16.0 +/- 5.0 mm Hg at a 4.0-mg dose of carbuterol (P less than 0.05). In patients with achalasia, the mean LES pressure decreased from 50.1 +/- 5.1 mm Hg to 22.7 +/- 2.4 mm Hg after a 4.0-mg dose of carbuterol (P less than 0.01). The duration of action following oral administration exceeded 90 min. These studies indicate that the LES in man has beta2-adrenergic receptors that mediate a reduction in pressure. The magnitude of LES pressure reduction in patients with achalasia suggests that this drug may be of therapeutic benefit.