012315 lower GI pharm

Question 1

diarrhea-when should you treat with pharmacological therapy

Answer 1

reserved for pts w significant or persistent symptoms (to provide symptomatic relief)

Question 2

narcotics used for anti-diarrheal therapy

Answer 2

loperamide

diphenoxylate

Question 3

loperamide

Answer 3

opioid derivative (opioids slow action of intestinal tract). mu receptor agonist
best agent-poorly penetrates CNS

Question 4

diphenoxylate

Answer 4

opioid derivative
mu receptor agonist
at high conc, can produce CNS effects–so there’s an abuse potential, so it’s given with atropine

Question 5

fiber

Answer 5

increases stool bulk

used to tx diarrhea and constipation

Question 6

bismuth subsalicylate

Answer 6

pepto bismo
MOA unclear
used to tx traveler’s diarrhea, episodic diarrhea

Question 7

what is used to tx diarrhea associated w carcinoid syndrome

Answer 7

octreotide (a somatostatin analog)-it inhibits hormone secretion

Question 8

side effects of octreotide

Answer 8

many–
short term: nausea, bloating
long term: gallstone

Question 9

two types of dietary fiber are used to tx constipation–what are they?

Answer 9

fermented fiber–colon bacteria ferments the fiber and produces short chain fatty acids which are somewhat prokinetic. fermentation increases stool bacterial mass. side effect: gas

nonfermented fiber-retains water and increases stool bulk

Question 10

Mg(OH)2

Answer 10

milk of magnesia
used to tx constipation
inorganic salts that aren’t absorbed, so causes water retention (osmotic)

Question 11

lactulose

Answer 11

osmotic laxative
it’s an unabsorbed carbohydrate. it’s metabolized to short chain fatty acids by gut bacteria

can decrease ammonia levels by acidifying

Question 12

polyethylene glycol (PEG)

Answer 12

to tx constipation

it’s not absorbed. retains water due to osmosis

Question 13

ducosate salts

Answer 13

to tx constipation

anionic surfactant that lowers surface tension

Question 14

contact cathartics/stimulant laxatives–ex and MOA

Answer 14

MOA: cause mucosa irritation/inflam

ex:
bisacodyl
senna

both act on large intestine

Question 15

lubiprostone

Answer 15

to tx constipation

activates Cl channels in intestine to increase water secretion

Question 16

use of lubiprostone

Answer 16

tx of adult chronic constipation and women w IBS

Question 17

linaclotide

Answer 17

to tx constipation
binds and activates the guanylate cyclase C receptor on luminal surface of intestinal epithelial cells to increase intracellular and extracellular cGMP.

its two effects:

• -Cl and bicarb secretion
• -extracecllular cGMP may decrease visceral pain

Question 18

use of linaclotide

Answer 18

chronic idiopathic constipation

IBS with constipation

Question 19

methylnaltrexone

Answer 19

selective antagonist of peripheral mu opioid receptor

used to tx constipation
used for opioid-associated consitipation

Question 20

prednisone

Answer 20

used to tx MODERATE/SEVERE ACUTE attacks of UC or Crohn’s

Question 21

budesonide

Answer 21

used to tx Crohn’s

ENTERIC release steroid used for Crohn’s
minimal side effects b/c not systemic like prednisone

Question 22

the 5-aminosalicylates

Answer 22

mesalamine
olsalazine
sulfasalazine

latter two are prodrugs that are converted to mesalamine by colonic bacteria

Question 23

use of 5-aminosalicylates

Answer 23

mild to moderate UC

Question 24

MOA of 5-aminosalicylates

Answer 24

unclear

Question 25

sulfasalazine side eeffects

Answer 25

related to the converted form sulfapyridine

fever, malaise, vomiting, headache

Question 26

mesalamine and olsalazine side effects

Answer 26

less side effects than sulfasalazine

Question 27

infliximab

Answer 27

used for mod/severe Crohn’s and UC