Effects of long-term treatment with oxytocin in chronic constipation; a double blind, placebo-controlled pilot trial.

Background: Oxytocin and its receptor have been found throughout the gastrointestinal (GI) tract, where it affects gut function. Clinically, we have no- ticed an improvement of bowel habits during lacta- tion in constipated women. The aim of this study was to examine whether oxytocin has an effect on bowel symptoms and psychological well being in women with refractory constipation. Methods: Fifty-nine women with refractory constipa- tion were included in a double blind, multicentre study. After a 2-week run-in period, they were ran- domly allocated to nasal inhalation of either placebo or oxytocin treatment twice daily for 13 weeks, followed by a 2 weeks, posttreatment period. The patients completed a questionnaire every day con- cerning bowel habits, abdominal pain and discomfort, and Gastrointestinal Symptoms Rating Scale (GSRS) and Psychological General Well-being (PGWB) twice during the study; namely, during the baseline period and at the end of the treatment period. Results: Both oxytocin and placebo led to improve- ment of the constipation according to the GSRS and led to improvement in the sensation of incomplete evacuation and anorectal obstruction, without signi- ficant differences between the groups. Abdominal pain and discomfort responded weakly to oxytocin, with no effect of the placebo. In a subgroup of patients with IBS and concomitant depression, a weak improvement in depressed mood was observed after oxytocin administartion. Conclusion: Nasal administration of oxytocin had no significant advantage over placebo concerning an effect on constipation. However, it seems to have a positive effect on abdominal pain and discomfort and depressed mood. These findings should be further explored.