Authors' affiliation: ¹Digestive Diseases Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. ²Masoud clinic, Kargar Shomali Avenue ,Tehran, Iran .

•Corresponding author and reprints: HomayoonVahedi MD, Digestive Disease Research Center, Tehran University of Medical Sciences, Tehran, Iran. 14117-13135-North Kargar Ave., Shariati hospital, Tehran-Iran. Tel: +98-21-82414-82415000, Fax: +98-21-82415400, E-mail: vahedi@ams.ac.ir

Accepted for publication: 20 February 2014

BACKGROUND: Irritable bowel syndrome (IBS) is a common disorder in Iran with challenging treatment. Although trials have suggested that probiotics alleviate the complaints of patients with minimal side effects, they have not been investigated in Iranian adults.
METHODS: In a randomized double-blind study, 108 eligible IBS patients (Rome III Criteria) aged 20 – 70 years who referred consecutively to a clinical center in Tehran with abdominal bloating from 2010 to 2012 received a combination probiotics or placebo twice daily for 4 weeks. The objective was to evaluate the efficacy and safety of a multi-strain probiotics combination. One week prior to and throughout the treatment, the participants recorded their abdominal symptoms on a daily basis, using visual analogue scale and reported satisfactory relief of general symptoms at the end of each week. Adverse events were evaluated by self-reporting and physical examination. Continuous variables were analyzed by independent t-test and chi-square was used for binomials.
RESULTS: The baseline characteristics were balanced (60% female, mean age 36.7 ± 11.5). A total of 97 (51 intervention, 46 control) completed the treatment. Intention to treat analysis was done on 108 allocated subjects. 85% of the probiotic group reported satisfactory relief of general symptoms compared with 47% in the control group (P < 0.01). A reduction in abdominal bloating and pain with probiotic was superior to placebo [-13.0 vs. -3.7 (P < 0.01), -8.2 vs. -2.1 (P = 0.02), respectively]. No severe adverse drug reaction was seen in either group.
CONCLUSIONS:  A 4-week period of treatment with the combination probiotics twice daily was safe, well tolerated, and effective in our patients. Further investigation is recommended for other subgroups of IBS. Trial Registration: IRCT.ir IRCT2012071010230N1