GI and acid-peptic dz's

Question 1

what are 3 acid-peptic dz’s?

Answer 1

GERD, peptic ulcer (gastric or duodenal), or stress-related mucosal injury

Question 2

over 90% of peptic ulcers are caused by…

Answer 2

infxn w/ H. pylori and use of NSAIDs

Question 3

where is the site of damage in H. pylori and NSAID induced ulcers?

Answer 3

H. pylori – duodenum

NSAIDs – stomach

Question 4

2 classes of drugs used in tx for acid-peptic dz’s?

Answer 4

agents that reduce intragastric acidity and those that promote mucosal defense

Question 5

what receptors do parietal cells contain?

Answer 5

gastrin (CCK-B)
histamine (H2)
acetylcholine (muscarinic, M3)

Question 6

what agents reduce intragastric acidity?

Answer 6

Antacids
H2 receptor antagonists (H2 blockers)
Proton Pump inhibitors (PPI)

Question 7

how do antacids neutralize the acidity in the stomach?

Answer 7

antacids = weak base

they react w/ gastric HCl to form a salt and water

Question 8

MOA antacids (sodium bicarbonate)

Answer 8

Reacts rapidly with hydrochloric acid (HCL) to produce carbon dioxide and sodium chloride

Question 9

ADE’s of antacids (sodium bicarbonate)

Answer 9

CO2 gastric distention and bleching, metabolic alkalosis, exacerbate fluid retention

Question 10

ADE’s antacids (calcium carbonate)

Answer 10

metabolic alkalosis

w/ dairy products –> hypercalcemia, renal insufficiency

Question 11

ADE’s antacids (Magnesium hydroxide or aluminum hydroxide)

Answer 11

(belching does not occur)

metabolic alkalosis, osmotic diarrhea, constipation

Question 12

what can be given w/ Magnesium hydroxide or aluminum hydroxide to control bowel function?

Answer 12

Gelusil, Maalox, Mylanta

Question 13

antacids should not be given within 2 hours of doses of…

Answer 13

Tetracycline
Fluoroquinolone
Itraconazole
Iron

Question 14

what are some H2 receptor antagonists (h2 blockers)?

Answer 14

Cimetidine (Tagament), ranitidine (Zantac), famotidine (Pepcid), nizatidine (Axid)

Question 15

what pts need a dose reduction of H2 receptor antagonists?

Answer 15

mod-severe renal insufficiency and elderly

Question 16

MOA of H2 receptor antagonists?

Answer 16

competitive inhibition at parietal cell H2 receptors

suppress acid secretion

highly selective

Volume of pepsin reduced

reduce acid secretion stimulated by histamine as well as by gastrin and cholinomimetic agents

histamine released from ECL cells by gastrin or vagal stimulation is blocked from binding to the parietal cell H2 receptor

direct stimulation by gastrin or acetylcholine diminished effect on acid secretion

Question 17

best time to give H2 blockers?

Answer 17

at bedtime

Question 18

which H2 receptor blocker is the most potent?

Answer 18

famotidine

Question 19

H2 receptor antagonists Rx vs. OTC duration of action?

Answer 19

rx = 10 hrs

OTC = 6 hrs

Question 20

uses of H2 blockers?

Answer 20

Gastroesophageal Reflux Disease (GERD)
Peptic Ulcer Disease (PUD)
Nonulcer Dyspepsia (NUD)
Prevention of Bleeding from Stress-Related Gastritis

Question 21

ADE’s for H2 receptor antagonists?

Answer 21

D, ha, fatigue, myalgias, constipation

mental status changes

Question 22

ADE’s of cimetidine?

Answer 22

inhibits binding of dihydrotestosterone to androgen receptors

males – gynecomastia, impotence

females – galactorrhea

crosses placenta

Question 23

Cimetidine drug interactions

Answer 23

Interferes (inhibitor) with several important hepatic cytochrome P450 drug metabolism pathways including: CYP1A2, CYP2C9, CYP2D6, and CYP3A4

Question 24

ranitidine drug interactions

Answer 24

binds 4–10 times less avidly than cimetidine to cytochrome P450

Question 25

what are some PPI's

Answer 25

``` Omeprazole (Prilosec) Esomeprazole (Nexium) Lansoprazole (Prevacid) Dexlansoprazole (Dexilant) Rabeprazole (Aciphex) **Pantoprazole (Protonix) ```

Question 26

when should you administer PPI's? why?

Answer 26

30-60mins before a meal preferably before breakfast PPIs inactivate acid pumps that are actively secreting, but they have no effect on pumps in quiescent

Question 27

Pharmacokinetics of PPI's

Answer 27

18 hours are required for synthesis of new H+/K+-ATPase pump molecules rapid first-pass systemic hepatic acid suppression by irreversible inactivation of PP

Question 28

PPI uses

Answer 28

GERD PUD Nonulcer dyspepsia Prevention of Stress-Related Mucosal Bleeding Gastrinoma and other Hypersecretory Conditions

Question 29

ADE's of PPI

Answer 29

hypersecretion if not tapered off diarrhea, ha, abd. pain promotes absorption of food-bound minerals (Fe, Ca, Mg) pneumonia, incr risk of C. diff

Question 30

PPI drug interactions

Answer 30

alter absorption of ketoconazole, digoxin omeprazole inhibit metabolism of warfarin, diazepam reduce clopidogrel activation **pantoprazole no significant drug interactions

Question 31

MOA Mucosal protective agents

Answer 31

Mucosal prostaglandins important in stimulating mucus/bicarbonate secretion and mucosal blood flow restrict back diffusion of acid and pepsin

Question 32

what are some Mucosal protective agents?

Answer 32

Sucralfate Prostaglandin analogs Bismuth

Question 33

How does Sucralfate work?

Answer 33

in water or acidic sol'ns --> forms viscous tenacious paste Stimulates mucosal prostaglandin and bicarbonate secretion

Question 34

uses for sucralfate?

Answer 34

prevention of stress-related bleeding

Question 35

pharmacodynamics of misoprostol (prostaglandin analogs)?

Answer 35

Both acid inhibitory and mucosal protective properties

Question 36

ADE's for misoprostol?

Answer 36

diarrhea, cramping, stimulates uterine contractions, dysmenorrhea, hypophosphatemia

Question 37

what are the 2 bismuth compounds available?

Answer 37

bismuth subsalicylate bismuth subcitrate potassium

Question 38

how does bismuth subsalicylate work?

Answer 38

undergoes rapid dissociation within the stomach, allowing absorption of salicylate Reduces stool frequency and liquidity in acute infectious diarrhea

Question 39

why does bismuth work for traveler's diarrhea?

Answer 39

has direct antimicrobial effects and binds enterotoxins

Question 40

ADE's for bismuth compounds

Answer 40

Harmless blackening of the stool and darkening of the tongue bismuth toxicity (encephalopathy), or salicylate toxicity avoid in renal insufficiency

Question 41

ADE's for sucralfate

Answer 41

constipation

Question 42

indications for Tx of H. pylori infection

Answer 42

Gastric or duodenal ulcer MALT lymphoma After endoscopic resection of gastric cancer Uninvestigated dyspepsia

Question 43

recommended 1st therapies for H. pylori infxn?

Answer 43

clarithromycin triple (PPI, clarithromycin, amox or metronidazole) bismuth quadruple (PPI, bismth subitrate, tetracycline, metronidazole) clarithromycin-based