Irritable Bowel Syndrome Exam 2

Question 1

What are the three subtypes of IBS?

Answer 1

• Constipation‐predominant (IBS‐C)
• Diarrhea‐predominant (IBS‐D)
• Mixed presentation (IBS‐M)

Question 2

Constipation‐predominant (IBS‐C)

Answer 2

• hard or lumpy stools ≥ 25% of the time and loose or watery stools <25% of the time
• Stool types 1 and 2 are considered hard and lumpy and are associated with IBS‐C

Question 3

Diarrhea‐predominant (IBS‐D)

Answer 3

• loose or watery stools ≥ 25 % of the time and hard or lumpy stools < 25% of the time
• Stool types 6 and 7 are more indicative of IBS‐D

Question 4

Mixed presentation (IBS‐M)

Answer 4

both hard/lumpy stools and watery, soft stools ≥ 25% of the time

Question 5

Treatment of IBS-C: Dietary fiber

Answer 5

• absorb water to bulk stools and promote passage

- first line

Question 6

Treatment of IBS-C: Bulk‐forming agents

Answer 6

• Psyllium (Metamucil), Polycarbophil (FiberCon; Fiber‐Lax; FiberGen), Methylcellulose (Citrucel)
• absorb water to bulk stools and promote passage

Question 7

Treatment of IBS-C: Osmotic laxatives

Answer 7

• Polyethylene glycol (Miralax)

- Osmotic agent which draws water into the stool and increases stool frequency

Question 8

Treatment of IBS-C: Stimulant laxatives

Answer 8

• Bisacodyl, senna

- Not routinely recommended but may be considered in severe constipation

Question 9

Treatment of IBS-C: Tegaserod (Zelnorm)

Answer 9

serotonin 5‐hydroxytryptamine 4 (5HT4) receptor agonist. Binds to 5HT4 receptor to stimulate peristaltic reflex and intestinal secretion

Question 10

Treatment of IBS-C: Lubiprostone (Amitiza)

Answer 10

• Chloride channel activator. Activates chloride channels to promote chloride movement into intestine to increase fluid secretion and motility
• Used in females >= 18 years old

Question 11

Treatment of IBS-C: Linaclotide (Linzess)

Answer 11

• increases levels of cyclic GMP (cGMP) and subsequently activates CFTR
• adults >= 18 years old
• Black Box warning: Avoid use in pediatric patients

Question 12

Treatment of IBS-C: Selective serotonin reuptake inhibitors (SSRIs)

Answer 12

fluoxetine; paroxetine; citalopram

Question 13

Treatment of IBS-D: Loperamide (Imodium)

Answer 13

Mu‐opioid receptor agonist, acts directly on circular and longitudinal intestinal muscles to inhibit peristalsis and prolong transit time; does not cross the blood‐brain barrier

Question 14

Treatment of IBS-D: Peppermint oil

Answer 14

antispasmodic to reduce colonic motility; possesses calcium‐channel blocking properties

Question 15

Treatment of IBS-D: Anti‐spasmodics

Answer 15

• dicyclomine (Bentyl); hyoscyamine (Levsin)

- block acetylcholine in intestine to inhibit smooth muscle contraction

Question 16

Treatment of IBS-D: Alosetron (Lotronex)

Answer 16

block serotonin 5‐hydroxytryptamine 3 (5HT3) receptors to regulate visceral pain, colonic transit, and gastrointestinal secretions

Question 17

Treatment of IBS-D: Eluxadoline (Viberzi)

Answer 17

Mu‐opioid receptor agonist and delta‐opioid receptor antagonist

Question 18

Treatment of IBS-D: Tricyclic Antidepressants (TCAs)

Answer 18

amitriptyline; imipramine

Question 19

Treatment of IBS-D: Rifaximin (Xifaxan)

Answer 19

nonabsorbable antibiotic; inhibits bacterial RNA synthesis in the GI tract

Question 20

Treatment of IBS-D and IBS-C

Answer 20

• Probiotics

- prevent disease‐causing bacteria from attaching to cell wall