Effects of sildenafil on esophageal motility of patients with idiopathic achalasia

Background & Aims: Sildenafil shows an intense and prolonged inhibitory eff ect on the smooth muscle cells of the human corpus cavernosum by blocking p hosphodiesterase type 5 that destroys nitric oxide-stimulated cyclic guanos ine monophosphate. We investigated if sildenafil possesses a similar effect on the esophageal musculature of patients with achalasia, where there is a n impairment of nitric oxide production similar to that of functional impot ence. Methods: In 14 patients affected by achalasia with an esophageal diam eter of 5 cm, esophageal motility was recorded with a low-compliance manome tric system. After a basal period of 30 minutes, a 50-mg tablet of sildenaf il dissolved in water was infused in the stomach in 7 patients and one of p lacebo in the other 7 patients, randomly and in double-blind manner, contin uing the recording for 60 minutes. Results: Lower esophageal sphincter tone , residual pressure, and wave amplitude after sildenafil showed a significa nt decrease compared with both the basal period and the placebo group, with a marked interpatient variability. The inhibitory effect reached its maxim um (about -50%) 15-20 minutes after the infusion and lasted <1 hour. Propag ation of pressure waves was not modified by sildenafil. Conclusions: Silden afil inhibits the contractile activity of the esophageal musculature of pat ients with achalasia, decreasing lower esophageal sphincter tone and residu al pressure as well as contraction amplitude.