IBS Irritable Bowel syndrome Prince Sattam Bin AbdulAziz University College Of Pharmacy Mohammad Ruhal Ain R Ph, PGDPRA, M Pharm (Clin. Pharm) Department of Clinical Pharmacy E-mal: Pharmaco-therapeutics 2

R.S is 32-year-old woman experiences intermittent crampy abdominal pain 3–5 days/week, bloating, and reduced frequency of bowel movements for the past 6 months. Before this, she had a bowel movement on a daily basis, and now, she reports a bowel movement every 2–3 days. She often needs to strain to evacuate her bowels. She reports that her symptoms do not appear to be related to specific foods. An extensive diagnostic work-up is negative, and she is given a diagnosis of IBS-C. Case 1

Define IBS? IBS is considered a functional GI disorder. The ACG 2009 guidelines define it as “abdominal pain or discomfort that occurs in association with altered bowel habits over a period of at least 3 months.”

Subtypes of IBS Definition divides IBS into the following subtypes a.Diarrhea predominant (IBS-D) b. Constipation predominant (IBS-C) c. Mixed IBS (IBS-M): Features of both IBS-D and IBS-C What subtypes of IBS R.S has ? Answer : Constipation predominant (IBS-C)

Pathophysiologyof IBS Involve alterations in both CNS and intestinal pain perception, alterations in GI motility and secretion, and contributions from current or past psychosocial factors, gas retention, and possibly previous GI infection or bacterial overgrowth.

IBS more common in ………………. (gender) WOMEN What socioeconomic class IBS is more predominant ? LOW IBS is more in patient ……………………………… (age) Younger than 50 years old Patients experience significant reductions in quality of life and use more health care resources. Comorbid psychiatric illnesses such as depression and anxiety may be present in a significant percentage of patients.

What are the symptoms of IBS beside diarrhea and constipation ? Diarrhea or constipation, pain is often a component of all subtypes. Other symptoms Bloating Distention Spasm Urgency may be present as well. Pain is often a component of all subtypes of IBS? T/F To diagnose IBS Typically a diagnosis of exclusion. Need to rule out other GI causes with thorough work-up ?T/F

Treatment strategies for IBS Treatment involves a mix of drug, diet, and psychosocial interventions. Cognitive behavioral therapy, dynamic psychotherapy, and hypnotherapy have all shown effectiveness in IBS. Dietary intervention involves avoidance of foods that trigger symptoms. Fill the blank Dietary intervention in IBS patient involves ……………………of foods that trigger symptoms. ?

Drugs used for IBS Antispasmodics: Used mostly for short-term relief of abdominal pain but may also treat diarrhea in patients with IBS-D I.Dicyclomine (Bentyl): Anticholinergic adverse effects II.Hyoscyamine (Levsin, LevsinSL), anticholinergic adverse effects III.Peppermint oil: Use enteric-coated products; may worsen GERD

Drugs used for IBS Tricyclic antidepressants (Treat pain, improve global symptoms, and slow motility in patient with IBS-D. Can be used in IBS-C but may worsen constipation I.Amitriptyline, nortriptyline, and imipramine II.Potential for anticholinergiceffects, sedation, CV effects, and drug interactions

Selective serotonin reuptake inhibitors (SSRIs)Treat pain and improve global symptomssimilar to tricyclicantidepressants. Used for both IBS-D and IBS-C Drugs used for IBS Tend to have a prokinetic effect, so may also improve constipation in IBS-C I.Fluoxetine, sertraline, citalopram, and paroxetin P.O. II. Side effects :-insomnia, sexual dysfunction, and withdrawal.

Drugs used for IBS Laxatives: Used for IBS-C Psylliumhas best evidence; however, it may cause bloating and gas formation. PEG-based laxatives (MiraLAX) may increase stool frequency, but they have fewer effects on reductions in abdominal pain. Minimal to no bloating Avoid stimulant laxatives because they may worsen abdominal pain. (example Senna)

Lubiprostone: FDA approved for IBS-C in women older than 18 years. Drugs used for IBS i.Chloride channel activator; improves motility and possibly pain ii.Dose is 8 mcg twice daily with meals for IBS-C. iii.Nausea and diarrhea are main adverse effects, costly as well

Drugs used for IBS Tegaserod (Zelnorm): 5HT4 partial agonist. FDA approved for IBS-C i. Improves pain, global symptoms, and motility Available on an emergency-use basis only because of its association with the development of CV events in women.

Loperamide i.No effects on global symptoms or pain, but reduces motility and increases stool consistency. ii.May be used as an adjunct to other therapies in IBS-D Drugs used for IBS

Probiotics: Some evidence to support improvement of global symptoms i. Lactobacilli given alone do not appear to be effective. ii. Bifidobacteria appears to be most efficacious. Combinations of bifidobacteria and other probiotic agents can also be used. Antibiotics: A short course (10–14 days) of nonabsorbable antibiotic may improve global symptoms of IBS, especially bloating. i. Rifaximin400 mg 2 or 3 times/day for 10–14 days has shown some efficacy. This agent is expensive and does not have an FDA-approved indication for IBS. ii. Limited data with neomycin and metronidazole

R.S is 32-year-old woman experiences intermittent crampy abdominal pain 3–5 days/week, bloating, and reduced frequency of bowel movements for the past 6 months. Before this, she had a bowel movement on a daily basis, and now, she reports a bowel movement every 2–3 days. She often needs to strain to evacuate her bowels. She reports that her symptoms do not appear to be related to specific foods. An extensive diagnostic work-up is negative, and she is given a diagnosis of IBS-C. Case

Question: Which one of the following therapeutic interventions is best for this patient? A.Amitriptyline50 mg daily. B. Senna 2 tablets twice daily. C. Hyoscyamine0.25 mg 4 times daily. D. Citalopram 20 mg once daily.

Questions: True and False Antispasmodics use to treat IBS-D ? T/F TricyclicAntidepressant can treat pain but can worsen constipation ? T/F SSRI can be used for both IBS-D and IBS –D (T/f) SSRI can improve IBS –C because of prokinetic effect? (T/F) Avoid stimulant laxatives because they may worsen abdominal pain. (example Senna) (T/F) Lubiprostone: FDA approved for IBS-C in women older than 18 years (T/F) Tegaserod(Zelnorm): 5HT4 partial agonist FDA approved for IBS-C and associated with increased CV event in women (T/F) Loperamide has no pain effect but used as adjunctive therapy for IBS- C (T/F)

References Symptoms in the Pharmacy: A Guide to the Management of Common Illness, 6th Edition Alison Blenkinsopp, P. Paxton and J. Blenkinsopp © 2009 Alison Blenkinsopp Updates in Therapeutics