GI Ulcers

Question 1

What are ways in which the gastric mucosa is protected?

Answer 1

mucous coating cells
tight junctions between cells (no HCl) passage
cell membrane impermeable to HCl
Bicarbonate in mucous = neutralizes
rapid turnover of cells
pepsinogen is inactive when secreted

Question 2

What stimulates HCl secretion in the GI?

Answer 2

parasympathetic innervation
Histamine - upregulate proton pump
cholinergic agonist
gastrin released from G cells (upregulate proton pumps)
- enteroendocrine cells and increase histamine

Question 3

How do the stimulates increase HCl?

Answer 3

trigger ATPase

• H+ out and K in
• Cl out

Question 4

What do proton pump inhibitor do?

Answer 4

shuts down ATPase H/K pump

Question 5

What is the one PPI approved for horses?

Answer 5

omeprazole (gastroguard)

Question 6

What uses of gastroguard?

Answer 6

short half life but long effect (irreversible inhibition)
high dose for treatment
lower dose fro prevention
relapse when off therapy
extra label in dogs (better tan famotidine

Question 7

what are the adverse events of gastroguard?

Answer 7

reduced gastric acid leads to hypergastrinemia
- more gastrin release = leads to mucosal cell hyperplasia, rugal hypertrophy and carcinoids
CYP enzyme inhibitor

Question 8

Does compounded omeprazole work?

Answer 8

yes but not nearly as effective as gastroguard

Question 9

How to H2 antagonists work?

Answer 9

blocks parietal cell HCl through H2 receptor inhibition

used in small animals

Question 10

What are 3 H2 blockers?

Answer 10

Cimetidine (tagamet) - dont give with food or antacid
Ranitidine (Zantac)
Famotidine (pepsid) - can give with food or antacid

Question 11

What is the PK of H2 blockers?

Answer 11

orally absorbed (low F in horses and ruminants)
lipid soluble
short half life
cYP inhibition (decrease metabolism of other drugs)

Question 12

What cured star gazing in dogs?

Answer 12

said to be “heart burn”

anti-HCl therapy

Question 13

What are side effects of stopping anti-ulcer medication?

Answer 13

increase serum gastrin and upregulation of the H2 receptors
increase parietal cell mass may occyr with chronic H2 or PPIs
increase sensitivity to histamine

Question 14

What are some antcids and what to they do?

Answer 14

AlOh, MgO, MgOH, CaCO3
- Maalox, Tums, Rolaids

MOA: neutralizes stomach acid to form water and neutral salt

Cheap safe but not dealing with problem

Question 15

What other two drugs are available for GI ulcers?

Answer 15

Sucralfate

Misoprotol

Question 16

What drug dissociates in gastric acid to sucrose octasulfate and AlOH to coat ulcers and increases mucosal PGE?

Answer 16

sucralfate

Question 17

What is MOA and use of Misoprostol?

Answer 17

synthetic PGE analogue, stimulates bicarbonate and mucous secretion, increases mucosal blood flow, decreases vascular permeability, increases cellular proliferation

USE: when administering steroids and NSAIDs
Few adverse events

Question 18

Is Misoprostol used for a preventative or treatment?

Answer 18

preventation

used with steroids and NSAIDs