Treatment of Acid Reflux and Peptic Ulcer Flashcards
What are direct stimulants to gastrin secretion?
Less Somatostatin release from D cells
Direct stimulation of G cells
What are vagal effects on gastrin release?
Gastrin releasing peptide stimulating G cells
Ach M3 receptor activation
What does ach M3 receptor do?
Inhibit the release of D cell product somatostatin
What does histamine stimulate?
H2 receptor in parietal cells to stimulate acid formation
What does gastrin bind to in order to activate ECL cells?
GG/CCK B receptor
What does gastrin bind to in order to activate parietal cells?
GG/CCK B receptor
What are the physiological actions of vagus nerve upon M3 receptors?
Direct ECL stimulation
Direct parietal cell stimulation
What affect does food have on pH/
Raises it and stimulates acid release through dietary peptides
What happens if a gastric antacid raises the pH of the stomach above 3.5-4?
Compensatory acid formation and the acid rebounds
What are four common antacids?
Sodium bicarbonate
Calcium bicarbonate
Aluminum hydroxide
Magnesium hydroxide
What may form from calcium bicarbonate?
Calcium phosphate kidney stones
What drug interactions are there with calcium bicarbonate?
Tetracyclines
Fluroquinolones
What occurs with immediate acid rebound?
Decreased somatostatin release
Decreased gastrin suppression
Increased gastrin release
What occurs in delayed chronic acid rebound?
ECL hyperplasia
Fundal polyp formation
Increased GERD
What are the pros of magnesium hydroxide and aluminum hydroxide?
Very effective with no acid rebound since they do not raise the pH high enough to get it
What does aluminum and magnesium cause respectively?
Aluminum: Intestinal irritant (constipation)
Magnesium: Laxative
What are the common H2 receptor antagonists?
Cimetidine, ranitidine, famotidine
Cons of H2 receptor antagonists?
Inhibit metabolism of other drugs causing toxicity
Why are PPI’s more commonly used than H2 receptor antagonists?
Because PPI’s are more expensive than H2 receptor antagonists
What way are PPI’s delivered?
Orally in an enteric coating and with delayed release since they are susceptible to acid and as a pro drug
How do PPI work?
By irreversibly binding to active proton pumps
What are the side effects of PPIs?
Fundal polyps (may or may not be cancerous), Zollinger-Ellison syndrome, increased gastrin which may act as a growth factor, C. difficile infections B12 deficiency Iron deficiency
What is Zollinger-Ellison syndrome?
Tumors growing in the pancreas or duodenum that release gastrin
What is an example of PPIs?
Omeprazole (all end in -prazole)
When do PPIs have their peak effect?
After a meal
What can NSAIDs cause?
Symptomatic GI ulceration
What can decrease NSAID ulcer forming capacity?
PPI
What is released by the stomach for protection?
PGI2 and COX-1
What is a prostaglandin type drug?
Misoprostol: methyl analog of PGE1
What is Pepto-Bismol?
Bismuth subsalicylate
How does Pepto-Bismol work?
Forms protective layer in stomach against pepsin and acid; binds enterotoxins; direct antimicrobial (against H. pylori)
What is sucralfate?
Sucrose salt complexed to sulfated aluminum hydroxide
How does sucralfate work?
Binds and coats negative sulfates to positively bound proteins exposed by ulcers to help heal them
What is H. pylori indicated in?
Gastritis
Peptic ulcer
Gastric cancer
MALT lymphoma
What is double, triple and quadruple therapy used for?
Eradication of H. pylori
What is double therapy?
Antibiotic + PPI
What is triple antibiotic therapy?
2 Antibiotics + PPI or bismuth
What is quadruple antibiotic therapy?
2 Antibiotics + PPI + bismuth
