IBS

• Irritable Bowel Syndrome (IBS)


  A functional gastrointestinal disorder, biopsychosocial chronic, relapsing disorder

  
• Symptoms of IBS may last a few days, weeks or months
• Causes of IBS


  • Alteration in gut motility
  • Intestinal hypersensitivity
  • Bacterial overgrowth
  • Neurotransmitters
  • Genetic factors
  • Food sensitivity
  • Stress

  
• Symptoms of IBS


  • Abdominal pain & cramps
  • Bloating
  • Distention
  • Diarrhea
  • Constipation

  
• Pharmacologic therapies for IBS


  Directed at relieving abdominal pain and discomfort and improving bowel function
• Drugs used for IBS with predominant diarrhea


  Antidiarrheal agents, especially loperamide, to reduce stool frequency and fecal urgency

  
• Drugs used for IBS with predominant constipation


  1. Fiber supplements to soften stools and reduce straining

  2. Osmotic laxatives to soften stools and promote increased stool frequency

  
• Drugs used for chronic abdominal pain in IBS


  Low doses of tricyclic antidepressants (e.g. amitriptyline or desipramine, 10–50 mg/d) to alter central processing of visceral afferent information and affect gastrointestinal motility and secretion

  
• Antispasmodics (Anticholinergics)


  Provide relief of abdominal pain or discomfort through anticholinergic activities, but spasm has not been found to be an important cause of IBS symptoms

  
• Commonly used antispasmodic medications


  • Dicyclomine
  • Hyoscyamine
• The efficacy of antispasmodics for relief of abdominal symptoms in IBS has never been convincingly demonstrated
• Tegaserod


  A serotonin 5HT4 receptor agonist used for treating women with IBS with constipation (IBS-C), but removed from market due to increased risk of cardiovascular events

  
• Lubiprostone


  A prostanoic acid derivative indicated for IBS-C, chronic idiopathic constipation, and opioid-induced constipation, acts by increasing intestinal motility and fluid secretion

  
• Linaclotide


  A new agent for chronic idiopathic constipation and IBS-C, stimulates guanylate cyclase to increase intestinal fluid and motility, may also decrease pain-sensing neuron activity

  
• Tenapanor


  An inhibitor of the sodium-proton exchanger (NHE3) which regulates sodium absorption and secretion, reducing sodium levels in the body
• Alosetron


  A selective serotonin 5-HT3 antagonist used in women with IBS-D, inhibits visceral afferent pain sensation and colonic motility

  
• Eluxadoline


  A new drug for IBS with diarrhea, acts as an agonist at opioid mu and kappa receptors and an antagonist at delta receptors, decreasing intestinal motility and relieving diarrhea

  
• Rifaximin


  A broad spectrum antibiotic indicated for IBS with diarrhea, has anti-inflammatory, antibacterial, and non-absorbable properties acting locally in the gut