20. Upper GI Pharmacology

Question 1

What are the 6 disorders of the GI tract?

Answer 1

Acidity 
Nausea 
Diarrhea 
Constipation 
Irritation 
Inflammation

Question 2

What are the 2 acid related disorders?

Answer 2

Ulcer

Gastro-esophageal reflux disease (GERD)- acid from stomach reflexes into esophagus, this burns the esophagus (heart burn) and can eventually cause serious damage

Slides 6-10

Question 3

What are buffering agents?

Answer 3

Ca carbonate
Mg, Al hydroxide

Simple to use, but not strong enough for many people
Use these because H + base -> neutral

Side effects are diarrhea from Mg and constipation from Ca, Al

Question 4

What are the 2 agents that decrease acid secretion?

Answer 4

H2 antagonists- ranitidine, reversible antagonists at H2 receptors, tolerance can develop
AE: well tolerated

Proton pump inhibitors- omeprazole, irreversible inhibition of the proton pump, binds to active proton pumps and inhibits
AE: well tolerated, long term use concerns, increase pH concerns about reduced absorption of nutrients, alteration in GI flora

Slides 15-27

Question 5

What are anticholinergics used in upper GI pharm?

Answer 5

Pirenzapine

Rarely used- poor efficacy, many side effects

Question 6

What are gastrin antagonists role in upper GI pharmacology?

Answer 6

In development

Question 7

What are the 2 mucosal defence agents?

Answer 7

1. Prostaglandins- misoprostol
2. Coating agents- sucralfate, bismuth subsalicylate (pepto bismol)

Slides 33-35

Question 8

What are prostaglandins?

Answer 8

Misoprostol
Prostaglandin analogue

Promotes secretion of mucous/bicarb
Inhibits acid secretion

AE: diarrhea, abdominal cramping, induced abortion

Question 9

What are the 2 types of coating agents?

Answer 9

Sucralfate- aluminum hydroxide + sucrose sulfate
Forms paste and stimulates mucous and bicarbonate secretion
AE: Al causes constipation

Bismuth salts- bismuth subsalicylate
Forms protective barrier on ulcer
Enhances mucous and bicarbonate secretion
Inhibits growth of H pylori and adherence to mucosa

Slides 39-41

Question 10

What are the 2 main causes of ulcer?

Answer 10

Helicobacter pylori (H pylori)- produces inflammatory changes in mucosa, impairs mucosal defence, increases acid secretion
If you have bacteria causing this you just kill it but before this was discovered ulcers wouldn’t go away

NSAIDs

Slides 42-

Question 11

How do you eradicate H pylori?

Answer 11

Combinations of drugs usually used
Proton pump inhibitor plus combinations of 2 or 3 antibiotics 
Common antibiotics used:
Amoxicillin 
Clarithromycin
Tetracycline
Metronidazole 
Bismuth

Slide 44

Question 12

What are the 4 future directions for curing ulcers? (Since antibiotics are becoming resistant)

Answer 12

Reversible proton pump inhibitors- toxicity issues have slowed development

Faster onset PPIs- remove coating, stim proton pumps

New motility agents for GERD- GABA agonists, glutamate antagonists

Target the acid “pocket”- alginic acid and buffers