Evaluation of available treatments for IBS


Other agents studied for the treatment of IBS

Loperamide,  Antidepressants, Serotonergic agents, PEG laxatives

Loperamide and its role in the treatment of IBS:

Key points based on the findings from the American College of Gastroenterology:3

  • Insufficient evidence to recommend loperamide for use in IBS based on the poor quality of evidence from available clinical trials.

Findings from the American Gastroenterological Association regarding Antisoasmodics:7

  • Very limited data available regarding the treatment of IBS-D with loperamide.
  • There is a large body of 'indirect' evidence to support use in reducing stool frequency and based on the low cost and minimal adverse effects can be viewed as a useful adjunct.
  • Statement:  use loperamide (over no drug treatment) in patients with IBS-D. (Conditional recommendation; Very low-quality evidence)

Use of antidepressants in IBS:

Key points based on the findings from the American College of Gastroenterology:3

  • Anxiety and depression are frequent comorbidities among IBS patients.
  • TCAs and selective serotonin reuptake inhibitors are effective in relieving symptoms of IBS -->  Recommendation: weak. Quality of evidence: high.
  • Majority of trials did not differentiate between the type of IBS treated.
  •  Incidence of adverse events was significantly higher among those taking antidepressants as compared with placebo.
  • Summary statement: Available evidence does not permit guidance on patient selection for antidepressant therapy.

Findings from the American Gastroenterological Association:7

  • Available evidence (low quality)  showed that TCA therapy resulted in a modest improvement in global relief and abdominal pain.
  • Represent a low-cost treatment option and should be used with caution in patients at risk for prolongation of the QT interval.
  • Final statements: 
    • May use tricyclic antidepressants (over no drug treatment) in patients with IBS. (Conditional recommendation; Low-quality evidence).
    • No evidence to support the use of selective serotonin reuptake inhibitors for patients with IBS.

Use of PEG laxatives in IBS:

Findings from the American College of Gastroenterology and the American Gastroenterological Association regarding PEG laxatives:3,7

  • Very low quality of available evidence.
  • AGC:  no available evidence to support PEG use in controlling symptoms of IBS.
  • AGA: Large body of indirect evidence of efficacy in treating constipation ---> PEG laxatives may be useful in patients with IBS-C (adjunct). Also few reported side effects and cost is low.
    Supports use of laxatives over no drug treatment.

Serotonergic agents in IBS:   Serotonin plays a critical role in gastrointestinal secretion, motility, and sensation while the serotonin subtype 3 (5-HT 3 ) receptors have been shown to play an important role in visceral pain.  5-HT 3 antagonists decrease pain from the gut and slow intestinal transit. Other receptor subtypes also impact the gastrointestinal tract.

Findings from the American College of Gastroenterology and the American Gastroenterological Association regarding PEG laxatives:3,7

  • Only one agent is recommended - 5-HT 3 antagonist (Alosetron) and it is restricted to women with severe diarrhea-predominant
    IBS. Alosetron can only be prescribed within a carefully monitored program because of the concerns regarding adverse events.

>Prosecretory agents (Linaclotide, Lubiprostone)


  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.  

Medical Calculators - A thru Z
Lab Values - A thru Z