Gastrointestinal Ulcers

Question 1

What roles does the gastric mucosa play in the GI tract?

Answer 1

protects the cells of the stomach from the acid and enzymes in the lumen of the stomach

Question 2

what type of cell secretes mucosa?

Answer 2

mucosal epithelial cells

Question 3

what cells are responsible for acid secretion?

Answer 3

parietal cells

Question 4

what is the role of HCl in the stomach?

Answer 4

to kill bacteria, viruses, and other parasites

Question 5

what can occur if there is an overproduction of HCl?

Answer 5

overwhelm the mucous layer and buffer systems, and lead to ulcers

Question 6

how do antacids work?

Answer 6

take NaHCO3 for example, it dissociates into Na+

the bicarbonate ion is absorbed into the blood and slightly increases the pH, which elevates the pH of the stomach

Question 7

what are some pros and cons to using antacids?

Answer 7

pro: quick, easy, and effective in the short term to reduce stomach acid the pt is currently experiencing
cons:
- alkalotic urine can increase the deposition of calcium and phosphate to form a kidney stone
- increases blood sodium, exacerbating hypertension
- acid rebound due to feedback regulation (pump more acid out in response to antacid directly increasing pH)

Question 8

what are the two categories of antacids? what is the difference?

Answer 8

systemic - NaHCO3
non-systemic - CaCO3, Al(OH)3, Mg(OH)2

non-systemic antacids do not effect extracellular or blood pH

Question 9

what is the concern regarding antacids that contain Al and Ca? how is this dealt with?

Answer 9

constipating effect

give with magnesium

Question 10

what do anticholinergics do in the treatment of overproduction of acid?

Answer 10

muscarinic Ach receptors in parietal cells stimulate HCl secretion from these cells; inhibition of these receptors reduces acid secretion, but not by much

Question 11

how much do anticholinergics decrease acid secretion? (in percentage)

Answer 11

up to 40%

Question 12

what are some side effects to anticholinergics?

Answer 12

dry mouth
vision problems
sedation, etc.

Question 13

what are cytoprotectives? give two examples

Answer 13

drugs which protect cells from acidic damage, either directly or through stimulation of mucus
ex: sucralfate, misoprostol

Question 14

how does sucralfate work?

Answer 14

it is an aluminum based salt that binds to hydrogen ions to form a gooey paste, increasing pH
also binds to degenerative cells, forming a protective layer
aka artificial mucous
works for 8-12h, specifically protects damaged tissue as well as reducing acidity

Question 15

how does misoprostol work?

Answer 15

prostaglandin analogue

stimulates production of mucosal barrier

Question 16

why do NSAIDs cause stomach problems?

Answer 16

COX inhibition causes PGE inhibition, and PGE is critical for mucous production in the stomach

Question 17

how does histamine H2 blockers work?

Answer 17

inhibition of H2 receptors (receptors on parietal cells that increase HCl production)
highly effective in a number of acid-related disorders

Question 18

what is the benefit to using H2 blockers?

Answer 18

very specific to the organ, so there are no adverse effects on the mucosa

Question 19

name 3 H2 blockers

Answer 19

cimetidine
ranitidine
famotidine

Question 20

by what percentage does cimetidine decrease stomach acid?

Answer 20

50-60%

Question 21

what are some side effects of cimetidine?

Answer 21

gynecomastia
reduced libido
impotence
all due to binding to androgen receptors

Question 22

by what percentage does ranitidine decrease stomach acid?

Answer 22

65-70%

Question 23

what is the benefit of using ranitidine over cimetidine?

Answer 23

does not bind to androgen receptor so no SE’s relating to that

Question 24

by what percentage does famotidine decrease stomach acid?

Answer 24

75%

Question 25

why is famotidine the H2 blocker of choice?

Answer 25

most effective at reducing acid secretion and has the best safety profile (very few SE's) works better at higher pH so given with antacid

Question 26

what do PPIs do?

Answer 26

inhibit gastric H/K ATPase proton pump responsible for pumping the H and Cl ions into the stomach PPIS enter the secretory canaliculus of parietal cell which opens when acid secretion occurs pro-drug is then converted to active drug PPIs bind very tightly to the channel, thus have a long half life

Question 27

by what percentage do PPIs decrease stomach acid?

Answer 27

90%

Question 28

give some examples of PPIs

Answer 28

omeprazole esomeprazole pantoprazole rabeprazole

Question 29

when are PPIs indiciated?

Answer 29

good for GERD | other acid-dependent disorders

Question 30

what additional benefit does rabeprazole have?

Answer 30

increases mucous secretion

Question 31

how does H. pylori cause an ulcer?

Answer 31

resides in stomach, wants to escape gastric acid, so it burrows into gastric mucosa produces urease, the enzyme that converts urea to ammonia and CO2 (CO2 causes lots of burping) this kills mucosal epithelial cells, leaving the gut unprotected

Question 32

what are the different tests available for testing for H pylori? which is the most popular?

Answer 32

breath test for urea and ammonia - popular serological - from stomach culture - from stomach histology - stool sample

Question 33

what is the first therapy option for H pylori infection?

Answer 33

triple therapy PPI (control acid) 2 effective antibiotics to kill the HP

Question 34

what is the next therapy option for those where triple therapy did not work?

Answer 34

quadruple therapy | PPI + 2 antibiotics + bismuth salicylate (protects stomach and make it easier for drug to reach disease)

Question 35

what is GERD?

Answer 35

lower esophageal sphincter defect allows acidic contents to contact the esophageal lining

Question 36

what kind of drugs can affect the LES tone?

Answer 36

beta blockers CCBs nicotine

Question 37

what are some non-pharms for GERD?

Answer 37

avoid fat, caffeine, chocolate, peppermint, and alcohol | avoid large meals, especially right before bed, stop smoking

Question 38

what is diarrhea?

Answer 38

frequent liquid stool | an intestinal disorder

Question 39

what are some causes of diarrhea?

Answer 39

``` foods bacteria virus drug SE's laxative abuse malabsorption syndrome stress bowel tumour ```

Question 40

what is the recommended treatment for diarrhea?

Answer 40

``` clear liquids (gatorade, pedialyte) BRAT diet ```

Question 41

when would we not want to stop diarrhea from occurring?

Answer 41

if caused by an infection; want to get rid of toxins

Question 42

what is one class of drugs that can be used to treat diarrhea?

Answer 42

opiates - decrease intestinal motility

Question 43

what are some side effects of opiates?

Answer 43

CNS depression | constipation

Question 44

name two opiate related agents?

Answer 44

1) diphenoxylate (lomotil) | 2) loperamide (imodium)

Question 45

what are some side effects to opiate-related agents?

Answer 45

drowsiness | distention

Question 46

what do adsorbents do? give some examples

Answer 46

coat the wall of the GI tract and adsorbing the bacteria or toxins causing diarrhea (substance takes in toxin) ex) kaopectate (kaolin and pectin), pepto-bismol