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Questions and Answers
What is the mechanism of action of proton pump inhibitors?
What is the mechanism of action of proton pump inhibitors?
- Stimulation of somatostatin release, leading to decreased gastric acid secretion
- Direct inhibition of pepsin activity, reducing protein digestion
- Competitive antagonism of histamine receptors, reducing gastric acid secretion
- Inhibition of the H+/K+ pump, resulting in decreased gastric acid secretion (correct)
Which of the following cell types is responsible for the release of histamine, which increases gastric acid secretion?
Which of the following cell types is responsible for the release of histamine, which increases gastric acid secretion?
- Regenerative (stem) cells
- Parietal cells
- Chief cells
- Enterochromaffin (EC) cells (correct)
Which of the following is NOT a potential side effect of proton pump inhibitors?
Which of the following is NOT a potential side effect of proton pump inhibitors?
- Increased risk of osteoporosis
- Increased gastric acid secretion (correct)
- Hypomagnesemia
- Vitamin B12 malabsorption
Which of the following cell types is responsible for the secretion of gastrin, which stimulates the release of gastric acid?
Which of the following cell types is responsible for the secretion of gastrin, which stimulates the release of gastric acid?
What is the main function of histamine H2 receptor antagonists in the treatment of peptic ulcer disease?
What is the main function of histamine H2 receptor antagonists in the treatment of peptic ulcer disease?
Which of the following conditions is NOT an indication for the use of proton pump inhibitors?
Which of the following conditions is NOT an indication for the use of proton pump inhibitors?
Which of the following cell types is responsible for the secretion of pepsinogen?
Which of the following cell types is responsible for the secretion of pepsinogen?
Which of the following is NOT a disadvantage of proton pump inhibitors compared to other drugs?
Which of the following is NOT a disadvantage of proton pump inhibitors compared to other drugs?
Which of the following medications is contraindicated in pregnancy due to its potential to stimulate uterine contractions?
Which of the following medications is contraindicated in pregnancy due to its potential to stimulate uterine contractions?
Which of the following medications is most likely to cause constipation as a side effect?
Which of the following medications is most likely to cause constipation as a side effect?
Which of the following treatments is considered 'triple therapy' for Helicobacter pylori infection?
Which of the following treatments is considered 'triple therapy' for Helicobacter pylori infection?
Which of the following statements is TRUE about the mechanism of action of sucralfate?
Which of the following statements is TRUE about the mechanism of action of sucralfate?
Which of the following medications is known to inhibit cytochrome P450 enzymes?
Which of the following medications is known to inhibit cytochrome P450 enzymes?
Flashcards
Cimetidine
Cimetidine
An antiulcer drug with antiandrogenic activity affecting libido and causing gynecomastia.
Gastric Antacids
Gastric Antacids
Aluminum and magnesium hydroxide or calcium carbonate that neutralize gastric acid for relief.
Sucralfate
Sucralfate
A cytoprotective drug that binds to ulcer craters to inhibit digestion by pepsin.
Helicobacter pylori
Helicobacter pylori
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Misoprostol
Misoprostol
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Peptic Ulcer Disease
Peptic Ulcer Disease
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Fundic Gland Cells
Fundic Gland Cells
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Parietal Cells
Parietal Cells
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Chief Cells
Chief Cells
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Proton Pump Inhibitors
Proton Pump Inhibitors
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Indications for PPIs
Indications for PPIs
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Histamine H2 Receptor Antagonists
Histamine H2 Receptor Antagonists
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Side Effects of PPIs
Side Effects of PPIs
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Study Notes
Peptic Ulcer Disease Treatment
- Peptic ulcer disease (PUD) is an ulcer in the gastrointestinal (GI) tract where gastric juice (pepsin and acid) causes mucosal breakdown. It reaches the submucosa layer.
- The layers of the GI tract from lumen to serosa are: lumen, mucosa, muscularis mucosae, submucosa, muscularis propria, and serosa.
- The stomach lining contains specialized cells:
- Parietal (oxyntic) cells produce intrinsic factor (vitamin B12 absorption) and hydrochloric acid (HCl) for pepsin activation.
- Chief (zymogenic) cells produce pepsinogen (converted to pepsin).
- Surface-lining mucus cells secrete mucus (containing prostaglandins).
- Regenerative (stem) cells replace damaged cells.
- Diffuse neuroendocrine system (DNES) cells secrete hormones.
- DNES cell subtypes and their functions:
- G cells: secrete gastrin, increasing HCl.
- D cells: secrete somatostatin, decreasing HCl.
- Enterochromaffin (EC) cells: secrete histamine, increasing HCl.
- Enterochromaffin-like (ECL) cells: secrete serotonin, stimulating motility.
- Gr cells: secrete ghrelin, promoting hunger.
Proton Pump Inhibitors (PPIs)
- PPIs (e.g., pantoprazole, lansoprazole, omeprazole, esomeprazole, rabeprazole) irreversibly inhibit the H+/K+ pump, reducing stomach acid.
- Indications: dyspepsia, PUD, Zollinger-Ellison syndrome, GERD, NSAID-induced PUD prophylaxis, MALT lymphoma.
- Side effects: hypomagnesemia, osteoporosis risk, vitamin B12 malabsorption, pneumonia and C. difficile infection risk, acute interstitial nephritis.
- Disadvantages: more side effects and interactions than other drugs.
Histamine H2 Receptor Antagonists
- These drugs (e.g., cimetidine, famotidine, ranitidine, nizatidine) block histamine H2 receptors, reducing stomach acid.
- Indications: dyspepsia, PUD, GERD.
- Side effects (mostly minimal, but cimetidine has notable ones):
- Cimetidine: antiandrogenic activity (gynecomastia, impotence, low libido) and cytochrome P450 inhibition.
- Disadvantages: lower efficacy than PPIs (healing time is longer).
Gastric Antacids
- Antacids (e.g., aluminum and magnesium hydroxide, calcium carbonate) neutralize stomach acid.
- Indications: symptomatic PUD relief.
- Side effects:
- Aluminum hydroxide: constipation, hypophosphatemia, seizures.
- Magnesium: diarrhea, hyporeflexia, hypotension.
- Calcium carbonate: constipation, milk-alkali syndrome (kidney injury, hypercalcemia, metabolic alkalosis), rebound acid secretion.
- Disadvantages: lower ulcer healing rates.
Cytoprotective Drugs
- Cytoprotective drugs (e.g., sucralfate, misoprostol) protect the stomach lining.
- Sucralfate: binds to ulcer crater proteins, inhibiting pepsin.
- Misoprostol: reduces acid and stimulates mucus secretion.
- Indications: PUD (sucralfate), NSAID-induced PUD prophylaxis (misoprostol).
- Side effects:
- Sucralfate: constipation, laryngospasm.
- Misoprostol: diarrhea, intestinal cramping.
- Disadvantages: low ulcer healing rates, misoprostol contraindicated in pregnancy.
Helicobacter pylori Infection Treatment
- Treat with eradication regimens (usually 10-14 days).
- Triple therapy: amoxicillin + clarithromycin + PPI (metronidazole if penicillin allergy).
- Quadruple therapy: metronidazole + PPI + bismuth subsalicylate + tetracycline.
- Confirm eradication after therapy (urea breath test or fecal antigen).
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