PHARM: Drugs for IBS

Question 1

What is the first line treatment of a patient with IBS?

Answer 1

education, reassurance, dietary modification (exclusion of gas producing foods), and increased physical activity

Question 2

When is drug treatment warranted with IBS?

Answer 2

for moderate to severe symptoms that are not relieved by lifestyle changes

Question 3

What type of IBS is treated with: Linaclotide, Lubiprostone, PEG?

Answer 3

IBS-C

Question 4

What type of IBS is treated with: Alostetron, Loperamide, Anti-spasmodics (Atropine, Dicyclomine, Glycopyrrolate)

Answer 4

IBS-D

Question 5

What type of IBS has: Hard or lumpy stools with ≥25% of BMs and loose watery stools with ≥25% of BMs?

Answer 5

IBS-M

Question 6

What type of IBS has: Presence of loose or watery stools with with ≥25% of BMs and hard or lumpy stools with <25% of BMs?

Answer 6

IBS-D

Question 7

What type of IBS has: Presence of hard or lumpy stools with ≥25% of BMs and loose watery stools with <25% of BMs?

Answer 7

IBS-C

Question 8

MOA: Osmotic agent; binds water and causes it to be retained within the stool AND stimulates stretch receptors to increase cholinergic activity in the ENS.

Answer 8

PEG

Question 9

MOA: Absorb liquid in GI tract; thereby altering intestinal fluid and electrolyte transport and causing stool expansion, increased peristalsis and bowel motility

Answer 9

Polycarbophil
Methylcellulose
Psyllium

Question 10

MOA: Activates guanylate cyclase-C receptor to increase intracellular cGMP→ sitmulates secretion of Cl- and CHO3- from CFTR ion channel into intestinal lumen and the increased GI fluid increases the GI transit (via stretch)

Answer 10

Linaclotide

Question 11

MOA: PGE1 derivative that directly activates plasma Cl- channel (ClC-2) to increase GI fluid secretion and accelerate motility (via stretch)

Answer 11

Lubiprostone

Question 12

What drug is STRONGLY recommended for IBS-C?

Answer 12

Linaclotide

Question 13

What is a contraindication for all IBS-C drugs?

Answer 13

Contraindicated in known/suspected obstruction.

Question 14

What IBS-C drug is contraindicated in children <6?

Answer 14

Linaclotide

Question 15

TOXICITY: Infrequent flatulence, nausea, abdominal pain, bloating and cramping

Answer 15

PEG

Question 16

TOXICITY: Rarely abdominal pain or cramps, diarrhea, increased flatulence, N/V

Answer 16

Polycarbophil
Methylcellulose
Psyllium

Question 17

TOXICITY: Diarrhea (usually within 2 weeks of treatment start)

Answer 17

Linaclotide

Question 18

TOXICITY: Dose related nausea, HA, and diarrhea

Answer 18

Lubiprostone

Question 19

MOA: Selective antagonist at 5-HT3 receptors extensively distributed on enteric neurons in GI tract.

Answer 19

Alosetron

Question 20

MOA: Competitive post-ganglionic muscarinic receptor antagonist. (modulate activity in the enteric nervous system)

Answer 20

Atropine
Dicyclomine
Glycopyrrolate

Question 21

MOA: Direct action on the circular and longitudinal muscles of the intestinal wall to slow motility. (modulates activity in the enteric nervous system)

Answer 21

Loperamide

Question 22

MOA: Selectively inhibits bacterial and mycobacterial DNA-dependent RNA polymerase. Reduces mucosal inflammation and barrier dysfunction induced by chronic stress by increasing population of lactobacillaceae.

Answer 22

Rifaximin

Question 23

Which drug for IBS-D has a BBW: not for pt w/ pre-existing colitis or severe constipation?

Answer 23

Alosetron

Question 24

What drug has severe constipation as an adverse effect (that can even lead to death)?

Answer 24

Alosetron

Question 25

What drug can rarely cause V tach and arrhythmia?

Answer 25

Alosetron

Question 26

Which drugs have systemic toxicity related to muscarinic antagonists: anhidrosis, flushing, bladder, vision and CNS dysfunction, s-TACH, impotence?

Answer 26

Atropine Dicyclomine Glycopyrrolate

Question 27

Does loperamide show any opiate-like or analgesic effects?

Answer 27

NO!

Question 28

What drug is a Oral rifampin analog?

Answer 28

rifaximin

Question 29

What is commonly seen with rifaximin treatment?

Answer 29

Increase in Lactobacilli and reduced segmented filamentous bacteria after treatment

Question 30

What types of adverse effects are seen with rifaximin?

Answer 30

GI symptoms: flatulence, N/V, fecal urgency, constipation, abdominal pain

Question 31

What is the ultimate pathway of action for drugs that are used in IBS-C?

Answer 31

increase stimulation of endogenous stretch receptors which, in turn, increases cholinergic activity, stimulate peristalsis and promote evacuation of the stool

Question 32

What is the ultimate pathway of action for drugs that are used in IBS-D?

Answer 32

by blocking neurotransmitter systems involved in gastric motility

Question 33

What is the important distinction between Lubiprostone and Linaclotide

Answer 33

Lubiprostone is a DIRECT activator of ClC-2 and Linaclotide is an INDIRECT activator of the CFTR (via increase in cGMP)*** Important

Question 34

What is the function of CIC-2 and CFTR?

Answer 34

channels are on apical surface of enterocytes that allow Cl- flow into the lumen

Question 35

What type of cells synthesize serotonin in the GI?

Answer 35

Enterochromaffin Cells

Question 36

List the function of intrinsic circuits of serotonin activity.

Answer 36

epithelial secretion/vasodilation OR for propulsive motility

Question 37

What are extrinsic circuits serotonin acts on?

Answer 37

vagal and spinal afferent fibers

Question 38

When does serotonin signaling end?

Answer 38

recovery phase

Question 39

What happens in the recovery phase?

Answer 39

5-HT is transported by SERT into epithelial cells where it is enzymatically degraded, or it enters the blood where it is transported into platelets and stored for further use

Question 40

What type of factors can also influence activity of the sympathetic and parasympathetic nervous systems and their effect upon modulating smooth muscle function in the intestinal wall?

Answer 40

psychosocial factors

Question 41

What is the MOA of tri-cyclic antidepressants?

Answer 41

reduce reuptake of NE and serotonin in CNS and some have strong anticholinergic activity

Question 42

What is the role of SSRIs?

Answer 42

enhance actions of 5-HT in CNS

Question 43

True or False: American Gastroenterological Association recommends using tricyclic antidepressants in the treatment of IBS

Answer 43

FALSE: they do NOT

Question 44

What can be used instead of TCAs to treat mood-related aspects of IBS?

Answer 44

SSRIs

Question 45

True or false: • Patients with both psychologic and drug treatment respond better than patients who have drug therapy alone

Answer 45

TRUE

Question 46

What may contribute to the increased activity of the enteric nervous system in IBS?

Answer 46

activation of inflammatory process

Question 47

What may signal the inflammatory process to begin in IBS?

Answer 47

dietary components or from the microflora in the intestinal lumen

Question 48

What substance is used by around 50% of IBS patients to self-medicate before seeking attention by a physician?

Answer 48

probiotics

Question 49

True or false: probiotics help with abdominal symptoms.

Answer 49

TRUE (in some studies)

Question 50

Are probiotics recommended in the treatment of IBS?

Answer 50

NO