Pharmacological management of different clinical presentations of IBS

1. Pharmacological Management
of Irritable Bowel Disease
Dr. M. Ahsan (MBBS, MD)

2. Case 1:
A 40 year old nurse at a busy community complains of nausea, epigastric pain, post-
prandial fullness/bloating, constipation, and left lower quadrant pain with bowel
movements since the last 4 years. The symptoms started following an episode of severe
diarrhea after a family picnic.
She usually has to take sick-leave due to her symptoms.
Her bowel habits include 2-3 small hard stools per week, generally mid-day, and she feels is
never completely emptied.
Pain is improved when she has a bowel movement, but she often strains to have a bowel
movement. She often gets abdominal pain which is even worse when she forgets to take
her fiber and drink plenty of water.
She has tried a paleo diet but felt it only helped for a few months.
She has had a colonoscopy and a recent H.pylori breath test. Both were negative.

3. Learning Outcomes…
• Describe the clinical features of IBS
• Diagnose IBS
• Describe the mechanism of action, uses and adverse effects of
different drugs used in IBS
• Describe the management of different types of IBS

4. Irritable Bowel syndrome
• Irritable bowel syndrome (IBS) denotes a mixed group of abdominal
symptoms for which no organic cause can be found
IBS could be due to:
Disorders of intestinal motility
Enhanced visceral perception
Microbial dysbiosis
Prevalence = 10-20%
Age at onset = ≤ 40 years
M:F = 1:2

6. Irritable Bowel syndrome: Diagnosis
IBS should be diagnosed only if, recurrent abdominal pain is associated
with at least 2 of:
Relief by defecation
Altered stool form
Altered bowel frequency
• Other symptoms: urgency, incomplete evacuation, abdominal
bloating, mucus with stool, worsening of symptoms after food
 Symptoms are chronic (> 6 months)
 Often exacerbated by:
 Stress
 Menstruation
 Gastroenteritis
 Antibiotics

7. Types of IBS

8. Management of IBS
• Diet
• Psychosocial modifications
• Drug therapy
Treatment should focus on controlling symptoms:
Initially using lifestyle/dietary measures, then cognitive therapy or
pharmacotherapy if required

9. Drug therapy for IBS
• Linaclotide
• Lubiprostone
• Alosetron
• Eluxadoline
• Rifaximin
• Dicyclomine
• Hyoscyamine

10. Linaclotide
MOA:
• Increases intestinal fluid secretion via increased cGMP
Use: IBS-C
Adverse effects:
• Diarrhoea, abdominal pain, flatulence, abdominal distension
• Contraindication: children < 17 years of age

11. Lubiprostone
MOA:
• Chloride channel activator
Use: Women with IBS-C
Adverse effects:
• Diarrhoea, abdominal pain, dyspepsia, headache, dizziness, and
hypotension

12. Alosetron
MOA:
• 5-HT3 antagonist
Use: Women with severe IBS-D
Adverse effects:
• Constipation, nausea & vomiting

13. Eluxadoline
MOA:
• µ opioid receptor agonist
Use: IBS-D
Adverse effects:
• Constipation, abdominal pain, risk of dependence & overdose

14. Rifaximin
MOA:
• Structural analog of rifampin  decreases bacterial load
Use: Short term use in IBS-D
Adverse effects:
• Nausea, fatigue, headache, dizziness, risk of Clostridium difficile
infection

15. Dicyclomine
MOA:
• Anticholinergic drug (decreases GI spasms and motility)
Use: IBS-C and IBS-D
Adverse effects:
• Anticholinergic side effects such as drowsiness and dry mouth

16. Hyoscamine
MOA:
• Anticholinergic antispasmodic drug
Use: IBS-C and IBS-D
Adverse effects:
• Anticholinergic side effects; overdose may produce hallucinations

17. Management: Constipation
• Ensure adequate water and fibre intake
• Promote physical activity
• Simple laxatives (avoid lactulose: it ferments and can aggravate
bloating)
• If the above fail: try one of the following 
 Increased fibre intake can worsen
bloating
 Avoid insoluble fibre such as bran
 Oats are better
prucalopride
linaclotide
lubiprostone

18. Management: Diarrhoea
• Avoid sorbitol sweeteners, alcohol and caffeine
• Reduce dietary fibre content
• Avoid ‘trigger foods’
• Use a bulking agent + loperamide after each loose stool

19. Management Colic/Bloating
• Diets low in fermentable, poorly absorbed saccharides and alcohol
(low FODMAP diet) can help
• Oral antispasmodics
• Combination probiotics can help flatulence
 FODMAP: fermentable oligo-, di-, and
monosaccharides and polyols
 Low FODMAP diet excludes garlic, onions,
beans, fruits, wheat-containing products
and sweeteners

20. Management of psychological symptoms/
visceral hypersensitivity
• Patients should be treated sympathetically
• Cognitive behavioral therapy
• Low dose of tricyclic antidepressant: amitryptyline

21. Thank you

22. References
• Lippincott Illustrated Reviews: Pharmacology(6th ed.). Philadelphia,
PA: Wolters Kluwer.
• Clinical Medicine: A Textbook for Medical Students &amp; Kumar PJ
and Clark ML (9th ed.); Elsevier Saunders
• Oxford Handbook of Clinical Medicine, 10th edition