Effects of sildenafil on esophageal motility of patients with idiopathic achalasia.

BACKGROUND & AIMS Sildenafil shows an intense and prolonged inhibitory effect on the smooth muscle cells of the human corpus cavernosum by blocking phosphodiesterase type 5 that destroys nitric oxide-stimulated cyclic guanosine monophosphate. We investigated if sildenafil possesses a similar effect on the esophageal musculature of patients with achalasia, where there is an impairment of nitric oxide production similar to that of functional impotence. METHODS In 14 patients affected by achalasia with an esophageal diameter of </=5 cm, esophageal motility was recorded with a low-compliance manometric system. After a basal period of 30 minutes, a 50-mg tablet of sildenafil dissolved in water was infused in the stomach in 7 patients and one of placebo in the other 7 patients, randomly and in double-blind manner, continuing the recording for 60 minutes. RESULTS Lower esophageal sphincter tone, residual pressure, and wave amplitude after sildenafil showed a significant decrease compared with both the basal period and the placebo group, with a marked interpatient variability. The inhibitory effect reached its maximum (about -50%) 15-20 minutes after the infusion and lasted <1 hour. Propagation of pressure waves was not modified by sildenafil. CONCLUSIONS Sildenafil inhibits the contractile activity of the esophageal musculature of patients with achalasia, decreasing lower esophageal sphincter tone and residual pressure as well as contraction amplitude.