Irritable Bowel Syndrome Diagnosis and Treatment

IBS is one of the most common digestive ailments according to the American College of Gastroenterology with  5 to 15 % of the general population affected. 1,2 The development and study of  pharmacologic treatment options is hindered by the complex pathophysiology of IBS. This syndrome  is characterized not by structural or biochemical abnormalities, but by symptoms of altered bowel function leading to abdominal pain or discomfort.   Also, because IBS is classified as a syndrome (characterized as a group of symptoms), single symptoms taken alone have little diagnostic value.  Diagnosis is based purely on clinical grounds.

The American College of Gastroenterology studied several treatment interventions for irritable bowel syndrome including3:

  • Diet and dietary manipulation
  • Fiber
  • Probiotics, prebiotics, antibiotics
  • Antispasmodics
  • Peppermint oil
  • Loperamide
  • Antidepressants
  • Psychological therapies, including hypnotherapy
  • Serotonergic agents
  • Prosecretory agents
  • Polyethylene glycol

The American Gastroenterological Association (AGA), also reviewed several treatment options4:

Options for IBS-C

  • Linaclotide
  • Lubiprostone
  • PEG laxatives

Options for IBS-D

  • Rifaximin
  • Alosetron
  • Loperamide

Options for IBS

  • Tricyclic Antidepressants
  • Selective Serotonin Reuptake Inhibitors
  • Antispasmodics


Irritable Bowel Syndrome Diagnosis

Access our IBS diagnosis calculator based on the Rome III criteria

Rome III Diagnostic Criteria for Functional Gastrointestinal Disorders. Appendix A. Accessed: July 2017.

In pathophysiology research and clinical trials, a pain/discomfort frequency of at least 2 days a week during screening evaluation is recommended for subject eligibility.


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  1. Lovell RM , Ford AC . Global prevalence of, and risk factors for, irritable bowel syndrome: a meta-analysis . Clin Gastroenterol Hepatol 2012; 10 : 712 – 21 .
  2. Quigley EM , Abdel-Hamid H , Barbara G et al. A global perspective on irritable bowel syndrome: a consensus statement of the World Gastroenterology Organisation Summit Task Force on Irritable Bowel Syndrome . J Clin Gastroenterol 2012 ; 46 : 356 – 66 .
  3. Ford AC, et al.   American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation Am J Gastroenterol 2014 109 Suppl 1 S2-S26. PubMed.
  4. Chang, L., Lembo, A., and Sultan, S. American Gastroenterological Association technical review on the pharmacological management of irritable bowel syndrome. Gastroenterology. 2014; 147: 1149-1172.
  5. Simren M,  Palsson OS,  Whitehead WE. Update on Rome IV Criteria for Colorectal Disorders: Implications for Clinical Practice.  Curr Gastroenterol Rep. 2017; 19(4): 15.  Published online 2017 Apr 3. doi: 10.1007/s11894-017-0554-0 PMCID: PMC5378729
  6. Drossman DA. Functional Gastrointestinal Disorders: History, Pathophysiology, Clinical Features and Rome IV. Gastroenterology. 2016;150:1262-1279.
  7. American Gastroenterological Association Institute Guideline on the Pharmacological Management of Irritable Bowel Syndrome. Accessed: July 2017. Available at:
  8. Zuckerman MJ. The role of fiber in the treatment of irritable bowel syndrome: therapeutic recommendations. J Clin Gastroenterol. 2006 Feb;40(2):104-8.
  9. LINZESS(R) package insert.  Allergan USA, Inc. Ironwood Pharmaceuticals, Inc. Irvine, CA 92612 Cambridge, MA, 02142.  Revised: 1/2017. Accessed: July 2017.
  10. Amitiza® (lubiprostone) package insert.  Takeda Pharmaceuticals America, Inc. Deerfield, IL 60015.  Revised: 9/2016.  Accessed: July 2017.