Efficacy of a Chinese Herbal Medicine in Providing Adequate Relief of Constipation-predominant Irritable Bowel Syndrome: A Randomized Controlled Trial.

BACKGROUND & AIMS: Irritable bowel syndrome (IBS) is the most common chronic functional bowel disorder, with few treatment options. IBS affects 10%-20% of the population; as many as 58% of patients have constipation-predominant IBS (IBS-C). We evaluated efficacy and safety of a standardized, specifically formulated Chinese herbal medicine (CHM) preparation in treatment of patients with IBS-C.

METHODS

We performed a double-blind trial of 125 patients with IBS-C (according to Rome III criteria), who were recruited from 13 medical centers or clinics in Australia from July 2009 through February 2012. Patients were randomly assigned to groups given a standardized extract of 7 selected CHM ingredients (n = 61) or placebo (controls, n = 64) for 8 weeks (5 capsules, twice daily). Subjects were then followed for 16 weeks. Chemical definition, standardization, and stability testing of the formulation were completed. Subjects completed a self-administered, validated binary questionnaire of global symptom improvement at weeks 2, 4, 8, and 16 (primary outcome). Secondary outcomes included results from the self-administered IBS Symptom Severity Scale and the Bristol Stool Form Scale (BSFS), which were completed at weeks 4, 8, and 16.

RESULTS

There was statistically and clinically significant (per protocol analyses) improvement among subjects who received CHM (n = 50) vs controls (n = 58) for 8 weeks. A greater proportion of subjects receiving CHM reported adequate relief (P = .010). Compared with controls, the CHM group had improved bowel habits vs controls at week 8, including lower IBS Symptom Severity Scale scores (P < .001), reduced straining during defecation (P = .002), and a significant decrease in hard lumpy stools (P = .031). The CHM group also had increased stool consistency, which was based on the Bristol Stool Form Scale (week 8, P < .001). There was no statistically significant difference between groups in abdominal pain at week 8 (P = .692). The CHM was well-tolerated.

CONCLUSIONS

In a prospective, controlled study, CHM reduced symptoms of IBS-C, increased bowel satisfaction and stool consistency, and reduced straining and hard lumpy stools, compared with placebo. Clinical trial registration no: ACTRN12609000558224.