Nizatidine enhances the gastrocolonic response and the colonic peristalticreflex in humans

Animal studies demonstrate that nizatidine, an H-2-receptor inhibitor, may enhance colonic activity independent of its effect on acid secretion. The e ffect of nizatidine on human colonic motility is unknown. We evaluated the potential prokinetic property of nizatidine in 12 healthy subjects (10 men and 2 women, age 21-46 years). Each subject received either nizatidine (600 mg), famotidine (80 mg, a H-2-receptor inhibitor used as a control), or a placebo, on separate days in randomized order at least 3 days apart. Follow ing an overnight fast, a three-lumen catheter fitted with a stimulus balloo n and two barostat bags was placed in the descending colon. The gastrocolon ic response was tested by antral balloon inflation and the colonic peristal tic reflex was evaluated by colonic distension. Changes in colonic motility were assessed by volume changes in the barostat bags. Antral distension ev oked volume-dependent increases in colonic motility, maximal at a 300-ml in flation, as demonstrated by a reduced bag volume. Nizatidine enhanced colon ic motility in response to antral distension at 200 and 300 ml, compared wi th famotidine and placebo. Colonic distension evoked volume-dependent incre ases in colonic motility proximal to the stimulus balloon. Compared with fa motidine and placebo, nizatidine enhanced the ascending and descending cont ractile limbs of the peristaltic reflex but did not affect relaxation dista l to the balloon. In conclusion, nizatidine enhanced the gastrocolonic resp onse and the colonic peristaltic reflex in healthy subjects. Further resear ch on the prokinetic action of nizatidine in the colon may lead to novel tr eatments for idiopathic constipation.