Sildenafil inhibits gastroduodenal motility

Background: Sildenafil shows an intense and prolonged inhibitory effect on the smooth muscle cells of corpus cavernosum arterioles by blocking phospho diesterase-type 5, which inactivates the nitric oxide-stimulated cyclic gua nosine monophosphate. Aim: To investigate whether this inhibitory effect is also displayed on the musculature of the gastroduodenal tract. Methods: In 16 normal subjects, antroduodenal motility was recorded by mean s of a low-compliance manometric system. Ten minutes after the appearance o f a phase III of the migrating motor complex, a tablet of sildenafil 50 mg, dissolved in 20 mL of water, was infused in the gut of eight patients, or a placebo in the other eight patients, randomly and in a double-blind manne r, continuing the recording for 90 min. The frequency and amplitude of antr al and duodenal waves, measured during the first 60 min after infusion in t he two groups, were compared statistically. In addition, the duration of an tral and duodenal phases I, and the number of phases III occurring during t he whole 90 min after infusion, were compared in the two groups. Results: Antral and duodenal wave frequency and amplitude were significantl y lower during the first 60 min after sildenafil administration. Both antra l and duodenal phases I were significantly longer after sildenafil than aft er placebo, and the number of phases III which occurred during the 90 min a fter sildenafil was significantly lower than after placebo. Conclusions: Sildenafil inhibits interdigestive motor activity of the antru m and duodenum.