Lubiprostone is an effective treatment for chronic constipation (CC). The mechanism of action of lubiprostone is through increasing fluid secretion and lubrication of the intestinal lumen. The effects of lubiprostone on gastrointestinal transit and small intestinal bacterial overgrowth (SIBO) have not been adequately explored. The current study was designed to investigate whether lubiprostone (1) alters gastrointestinal transit and (2) affects SIBO in patients with constipation.Methods
A total of 29 female patients (mean age = 39 years; range: 19-64) with CC received 2 weeks of lubiprostone (24 mcg b.i.d., P.O.). Stool consistency based on Bristol stool scale and the frequency of bowel movements (BMs) were recorded. Gastric emptying time, small bowel transit time, colon transit time (CTT), combined small and large bowel transit time (SLBTT) and whole gut transit time were measured using wireless motility capsule. The SIBO status was assessed by the lactulose breath test. Data were analyzed using Wilcoxon rank, Mann-Whitney U, Spearman's rank correlation and Chi-square tests.Results
Lubiprostone significantly softened the stool and increased the frequency of BM from median of 2 to 4 times per week. The CTT and SLBTT were significantly shorter in responders to lubiprostone (i.e., those with ≥ 2 times increase in the number of their weekly BM) compared with nonresponders. The higher frequency of BM after treatment was significantly correlated with the acceleration of CTT, SLBTT and whole gut transit time. In all, 17 out of 25 (68%) patients, who were tested for SIBO at baseline, were positive. In addition, 7 out of 17 (41%) SIBO-positive patients became SIBO-negative after lubiprostone treatment (P < 0.05).Conclusions
In CC, lubiprostone improves the frequency of BMs, softens the stool, accelerates intestinal transit and decreases accompanying SIBO. The improvement of SIBO could be explained by the cleansing effect of increased intestinal fluid and mucus combined with enhanced intestinal motility with lubiprostone.