GI Pharmacology 1

Question 1

antacids - MOA

Answer 1

directly neutralize acid in the stomach (antacids are weak bases)

Question 2

antacids - specific drugs

Answer 2

*calcium carbonate!! (tums)
*magnesium hydroxide
*aluminum hydroxide
*sodium bicarbonate (no longer recommended)

Question 3

antacids - uses

Answer 3

*dyspepsia
*GERD

Question 4

antacids - adverse effects

Answer 4

*belching
*metabolic acidosis
*diarrhea (Mg)
*constipation (Ca & Al)

note - oftentimes Mg and Al are combined to avoid diarrhea vs. constipation

Question 5

antacids - drug interactons

Answer 5

*di- and tri-valent cations bind drugs (fluoroquinolones; tetracyclines)
*some drugs require acid for absorption (ketoconazole)

Question 6

famotidine - drug class & MOA

Answer 6

*drug class: H2-receptor antagonist
*MOA: competitive inhibition of parietal cell H2-receptor

Question 7

famotidine - uses

Answer 7

*GERD (PPIs are better)
*peptic ulcer disease (PPIs are better)
*non-ulcer dyspepsia
*stress GI bleeding prevention

Question 8

proton pump inhibitors (PPIs) - drugs in class

Answer 8

*omeprazole
*pantoprazole
*lansoprazole

Question 9

proton pump inhibitors - MOA

Answer 9

block the final common pathway of acid secretion by IRREVERSIBLY inactivating the parietal cell proton pump (H+/K+ ATPase)

Question 10

proton pump inhibitors - uses

Answer 10

*GERD
*peptic ulcer disease
*esophagitis
*dyspepsia
*hypersecretory diseases
*stress GI bleeding prevention

Question 11

proton pump inhibitors - unique facts

Answer 11

*products are inactive prodrugs (need to be activated)
*acid labile (oral products are in “acid resistant” form)
*give on empty stomach

Question 12

proton pump inhibitors - adverse effects

Answer 12

*decreased vitamin B12 absorption
*osteoporosis
*increased risk of C. diff

Question 13

omeprazole - drug class & MOA

Answer 13

*proton pump inhibitor
*irreversibly inactivates the parietal cell proton pump (H+/K+ ATPase)

Question 14

pantoprazole - drug class & MOA

Answer 14

*proton pump inhibitor
*irreversibly inactivates the parietal cell proton pump (H+/K+ ATPase), reducing production of gastric acid

Question 15

sucralfate - drug class & MOA

Answer 15

*drug class: mucosal protective agent
*MOA: forms a viscous paste that binds to injured tissues such as ulcers

Question 16

sucralfate - uses

Answer 16

*prevent stress ulcer bleeding

Question 17

misoprostol - drug class & MOA

Answer 17

*drug class: mucosal protective agent
*MOA: analogue of prostaglandin E (PGE1); counteracts the effects of NSAID-inhibition of prostaglandin synthesis

Question 18

misoprostol - uses

Answer 18

*prevent NSAID-related ulcers
*not used a lot now

Question 19

misoprostol - key thing to know

Answer 19

abortifacient (can cause spontaneous abortion) - don’t give to a pregnant patient for GI stuff

Question 20

celecoxib - MOA, uses

Answer 20

*COX-2 inhibitor (NSAID that hits COX-2)
*used as an anti-inflammatory with less GI toxicity

Question 21

bismuth compounds - MOA, uses, drugs in class

Answer 21

*MOA: coats ulcers, kills H. pylori, etc
*uses: dyspepsia, traveler’s diarrhea, tx H. pylori
*drug = Pepto-bismol (bisubsalicylate)

note - can turn tongue & stool black

Question 22

neostigmine - drug class, MOA, uses, ADEs

Answer 22

*drug class: promotility agent
*MOA: acetylcholinesterase inhibitor (cholinomimetic); enhances emptying of stomach, small bowel, & colon
*uses: post-surgical ileus or acute colonic pseudo-obstruction
*ADEs: parasympathetic actions - increased salivation, nausea, vomiting, diarrhea, bradycardia

Question 23

metoclopramide - drug class, MOA, uses, ADEs

Answer 23

*drug class: promotility agent
*MOA: D2 receptor antagonist
*uses: impaired gastric emptying & diabetic gastroparesis
*ADEs: restlessness, drowsiness, insomnia, agitation, EPS

Question 24

H. pylori treatment strategy

Answer 24

*generally 2+ antibiotics and a PPI, +/- bismuth
*currently, BISMUTH + TETRACYCLINE+ METRONIDAZOLE + PPI (proton pump inhibitor)

Question 25

erythromycin - drug class, MOA, uses (in GI), ADEs

Answer 25

*drug class: macrolide + promotility agent
*MOA: directly stimulates motilin receptor
*uses: gastroparesis
*ADEs: nausea & vomiting

Question 26

ondansetron - drug class, MOA, uses, ADEs

Answer 26

*drug class: 5-HT3 antagonists
*MOA: block peripheral 5-HT3 receptors
*uses: chemo-induced & post-op nausea & vomiting
*ADEs: well-tolerated, but: headache, constipation, diarrhea, QTc prolongation

Question 27

what anti-emetic is used for chemotherapy-induced nausea and vomiting

Answer 27

ONDANSETRON (serotonin 5-HT3 antagonist)

Question 28

prochlorperazine & promethazine

Answer 28

*block dopamine receptors
*used to treat nausea & vomiting
*drug class = phenothiazine
*ADEs: EPS, sedation

Question 29

dronabinol (THC)

Answer 29

*major psychoactive ingredient in marijuana
*used clinically as appetite stimulant & antiemetic
*ADEs: euphoria, dysphoria, sedations, hallucinations, dry mouth, tachycardia

Question 30

ursodeoxycholic acid (ursodiol) - drug class, MOA, uses, ADEs

Answer 30

*drug class: bile acid
*MOA: incorporated into bile acid pool
*uses: dissolve or prevent gallstones; PRIMARY BILIARY CHOLANGITIS!!
*ADEs: diarrhea

Question 31

cholestyramine - drug class, MOA, uses, ADEs

Answer 31

*drug class: bile acid binder
*MOA: bind bile acid in GI tract (anion exchange resin)
*uses: bile acid diarrhea; pruritis due to partial biliary obstruction
*ADEs: bloating, flatulence, constipation, fecal impaction
*note - binds and prevents absorption of many drugs

Question 32

what drug is used to treat primary biliary cholangitis

Answer 32

URSODIOL [ursodeoxycholic acid] (replaces the more toxic endogenous bile acids and has anti-inflammatory effects)

Question 33

treatment strategy for eosinophilic esophagitis

Answer 33

*ALWAYS: proton pump inhibitor AND topical steroids

*sometimes:
-systemic steroids
-montelukast
-mepolizumab