Gastrointestinal Drugs Overview
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Questions and Answers

What is the primary cause of GERD in terms of the esophageal sphincter?

  • Overproduction of insulin
  • Underproduction of pepsin
  • Over relaxation of the Lower Esophageal Sphincter (correct)
  • Hyperactivity of the diaphragm

    • Which of the following factors does NOT contribute to Peptic Ulcer Disease?

  • Excess acid production
  • Intrinsically defective mucosal barrier
  • High fiber diet (correct)
  • H.pylori infection

    • What is a potential complication of long-term NSAID use?

  • Increased mucosal defense strengths
  • Enhanced gastric mucosa restoration
  • Decreased prostaglandin production (correct)
  • Stimulated gastrin secretion

    • What type of tumors are associated with Zollinger-Ellison Syndrome?

    <p>Duodenal or pancreatic tumors that secrete gastrin</p> Signup and view all the answers

    Which of the following agents can inhibit acid secretion?

    <p>Prostaglandins</p> Signup and view all the answers

    Which mechanism is primarily involved in the hormonal regulation of gastric acid?

    <p>CCK2 receptor activation</p> Signup and view all the answers

    Which condition is classified as a result of physical trauma leading to acid exposure?

    <p>Stress ulcers</p> Signup and view all the answers

    What is the primary action of sucralfate in treating acid-peptic disorders?

    <p>Forms a viscous paste that adheres to mucosa</p> Signup and view all the answers

    Which of the following accurately describes the pharmacokinetics of domperidone?

    <p>Low oral bioavailability and does not cross the blood-brain barrier</p> Signup and view all the answers

    Which prokinetic drug is known for crossing the blood-brain barrier?

    <p>Metoclopramide</p> Signup and view all the answers

    What major neurotransmitter does metoclopramide indirectly promote to enhance gastric emptying?

    <p>Acetylcholine</p> Signup and view all the answers

    What type of medication is indicated for the treatment of GERD, gastroparesis, and severe refractory constipation?

    <p>Prokinetic drugs</p> Signup and view all the answers

    Which signaling pathway primarily stimulates parietal cell acid secretion?

    <p>cAMP pathway</p> Signup and view all the answers

    What is the primary role of H2 receptor antagonists in gastric acid secretion?

    <p>Inhibit histamine-induced cAMP increase</p> Signup and view all the answers

    Which of the following substances directly inhibits parietal cell acid secretion?

    <p>Prostaglandin E2 (PGE2)</p> Signup and view all the answers

    What effect does acetylcholine have on parietal cells?

    <p>Stimulates acid secretion</p> Signup and view all the answers

    Which receptor pathway is enhanced by histamine in parietal cells?

    <p>H2 receptor pathway</p> Signup and view all the answers

    How does the EP3 receptor affect cAMP levels in parietal cells?

    <p>Decreases cAMP levels</p> Signup and view all the answers

    What is the primary function of gastrin in gastric physiology?

    <p>Stimulate gastric acid secretion</p> Signup and view all the answers

    Which of the following is a potential outcome of increased cAMP levels in parietal cells?

    <p>Increased proton pump activity</p> Signup and view all the answers

    What effect does PGE2 have on gastric acid secretion?

    <p>Inhibits acid secretion</p> Signup and view all the answers

    What is the primary function of H+, K+-ATPase in parietal cells?

    <p>To facilitate the secretion of hydrogen ions</p> Signup and view all the answers

    What role does intracellular ATP play in the function of H+, K+-ATPase?

    <p>It provides energy for the proton pump</p> Signup and view all the answers

    What is the effect of omeprazole on gastric acid production?

    <p>Irreversibly inhibits acid production</p> Signup and view all the answers

    Why is omeprazole considered a prodrug?

    <p>It requires low pH conditions to become active</p> Signup and view all the answers

    Which metabolic pathway is primarily responsible for the metabolism of omeprazole?

    <p>CYP2C and CYP3A pathways</p> Signup and view all the answers

    What is a significant consequence of inhibiting H+, K+-ATPase?

    <p>Reduced gastric acid secretion</p> Signup and view all the answers

    What is the significance of esomeprazole in relation to omeprazole?

    <p>It is a more potent form of omeprazole</p> Signup and view all the answers

    What would be the result of taking omeprazole with other acid-suppressing agents?

    <p>Reduced effectiveness of both agents</p> Signup and view all the answers

    What is the desired timing for taking omeprazole to maximize its efficacy?

    <p>Just prior to a meal</p> Signup and view all the answers

    Which of the following statements about the effect of omeprazole is true?

    <p>It forms a covalent bond with the proton pump</p> Signup and view all the answers

    What is the main action of Proton Pump Inhibitors (PPIs) like rabeprazole?

    <p>Inhibiting H+, K+-ATPase</p> Signup and view all the answers

    Which side effect is commonly associated with the use of Cimetidine?

    <p>Hypergastrinemia</p> Signup and view all the answers

    Which of the following drugs is considered a competitive H2 receptor antagonist?

    <p>Famotidine</p> Signup and view all the answers

    What is one of the primary mechanisms of action for Misoprostol?

    <p>Increasing mucus secretion</p> Signup and view all the answers

    Which statement regarding antacids is FALSE?

    <p>They do not affect gastric pH</p> Signup and view all the answers

    What is a characteristic of Ranitidine compared to Cimetidine?

    <p>Same mechanism but longer duration of action</p> Signup and view all the answers

    Which side effect is associated with Prostaglandin E1 analogs like Misoprostol?

    <p>Abortion</p> Signup and view all the answers

    What effect do anticholinergics like Pirenzepine have on acid secretion?

    <p>Moderately block acid secretion</p> Signup and view all the answers

    Which characteristics apply to Aluminum hydroxide as an antacid?

    <p>Slow onset and moderate duration</p> Signup and view all the answers

    What is a primary advantage of Famotidine compared to Cimetidine?

    <p>Longer duration and fewer drug interactions</p> Signup and view all the answers

    Study Notes

    Gastrointestinal Drugs

    • Gastroesophageal Reflux Disease (GERD): Acid and pepsin from the stomach flow backward into the esophagus, often called heartburn.
    • Causes of GERD:
      • Overproduction of acid/pepsin
      • Over relaxation of the Lower Esophageal Sphincter (LES)
    • Peptic Ulcer Disease: A benign lesion of gastric or duodenal mucosa.
    • Causes of Peptic Ulcer Disease:
      • Excess acid production
      • Intrinsic defect in the mucosal defense barrier
      • Helicobacter Pylori (H. pylori) infection (most ulcers)
      • Medication use (nonsteroidal anti-inflammatory drugs (NSAIDs))
      • Gastrinoma (Zollinger-Ellison Syndrome)
      • Stress ulcers
    • Strategies for Protecting the Gastric Mucosa:
      • Mechanisms: Inhibit acid secretion, prevent contact, neutralize acid
      • Examples:
        • Cimetidine
        • Omeprazole
        • Prostaglandins
        • Muscarinic antagonists
        • Sucralfate
        • Antacids
    • Multiple Mechanisms Regulate Gastric Acid:
      • Hormonal factors: Gastrin, Histamine, Acetylcholine
      • Paracrine factors: Histamine
      • Neural factors: Acetylcholine
    • Strategies for Inhibiting Parietal Cell Acid Secretion: Gastrin antagonists, Histamine antagonists, Muscarinic antagonists
    • H+, K+-ATPase (proton pump): Final transport pathway for parietal cell hydrogen ion secretion.
      • Located in the apical membrane.
      • Requires intracellular ATP
      • Inhibition blocks both basal and stimulated acid secretion.
    • Omeprazole (Prilosec): Prototype H+, K+-ATPase inhibitor, prodrug needing low pH to be active. Irreversible inhibition of acid production.
      • Profound reduction of gastric acid with significant pH elevation (20mg/day for 7 days can reduce acid by 95%)
      • Highly protein-bound, metabolized by CYP2C & CYP3A. Short half-life (1-2hours), but long duration of action. Taken just prior to a meal and not with other acid-suppressant medications.
    • Esomeprazole, Rabeprazole, Lansoprazole, Pantoprazole: H+, K+-ATPase inhibitors. Esomeprazole is an isomer of omeprazole. Pantoprazole is acid stable and given intravenously.
    • Proton Pump Inhibitors (PPI) Side effects: Well tolerated, but hypergastrinemia (can lead to tumor growth), nausea, headaches, and skin rashes.
    • Histamine H2 Antagonists: Cimetidine, Ranitidine, Famotidine, Nizatidine.
    • Cimetidine: Competitive H2 receptor antagonist. Markedly inhibits basal acid secretion, including nocturnal secretion. Readily absorbed, relatively brief duration of action. Given multiple times daily.
    • Ranitidine, Famotidine, Nizatidine: Similar mechanisms to Cimetidine but longer duration of action (8-12 hours). Can be administered less frequently.
    • Anticholinergics: Pirenzepine, Telenzepine. Block acetylcholine at muscarinic (M3) receptors; effectively block acid secretion (30-40%). But limited by side effects.
    • Prostaglandins (PGE2 & PGI2): Act on prostaglandin EP3 receptors on parietal cells and epithelial cells. Inhibit acid secretion and gastrin release. Stimulate mucus, bicarbonate secretion, and mucosal blood flow. Cytoprotective.
    • Misoprostol (Cytotec): Synthetic analog of prostaglandin E1. Anti-acid secretory. 0.1 to 0.2 mg results in 85% to 95% reduction in acid secretion to prevent NSAID gastric ulcers
      • Side effects: Diarrhea, abortion.
    • Antacids: Weak bases neutralizing HCl in the stomach, raising gastric pH.
      • Magnesium hydroxide
      • Magnesium trisilicate
      • Magnesium-aluminum mixtures
      • Calcium carbonate
      • Sodium bicarbonate
    • Sucralfate: Basic aluminum salt of sucrose octasulfate. Forms viscous paste adheres strongly to gastric and duodenal mucosa, especially to partially denatured proteins.
    • Role of H. Pylori in Peptic Ulcer Disease: Eradication of the bacteria, along with inhibition of acid, is the treatment. Combination therapy with Omeprazole and Amoxycillin is common.
    • Functional Disorders of the GI (loss of normal bowel movement patterns): Primary: infections, inflammation, congenital defects. Secondary: metabolic disorders, neurological disorders (diabetes mellitus).
    • Prokinetic Drugs: Enhance transit of materials through the GI tract (enhance GI motility). Increase neuromuscular transmission.
      • Used for: Gastroesophageal reflux disease (GERD), Gastroparesis, Nighttime heartburn, Severe refractory constipation (sometimes caused by irritable bowel syndrome (IBS)). Increase action of other GI drugs.
      • Metoclopramide (Reglan): Antiemetic, improves gastric emptying by indirectly releasing acetylcholine, dopamine receptor antagonist.
        • Side effects: Sedation, dystonic reactions, anxiety, gynecomastia, galactorrhea.
      • Domperidone (Motilium): Antiemetic, improves gastric emptying, dopamine receptor antagonist, ganglionic stimulant
        • Side effects: Headaches, gynecomastia
    • Anti-emetics: Metoclopramide, Domperidone, ondansetron, granisetron, hyoscine, atropine, cyclazine, promethazine, chlorpromazine, haloperidol
    • Diarrhea: A condition of having at least three loose stools or liquid bowel movements each day, often due to viral, bacterial, or parasitic infection.
    • Treatment of Diarrhea: Replacement of fluid and electrolytes (ORS - oral rehydration salts). Treatment of the cause (like an antibiotic if needed). Antidiarrheal agents (adsorbents like kaolin, pectin). Anti motility drugs (codeine).
    • Laxatives: Drugs that promote defecation or passage of stools. Mild action (laxatives), stronger action (cathartics and purgatives).
    • Types of Laxatives: Luminally active agents (Hydrophilic colloids, osmotic agents), Nonspecific stimulants or irritants, Prokinetic agents.

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    Gastrointestinal Drugs PDF

    Description

    This quiz explores essential gastrointestinal drugs focusing on GERD and Peptic Ulcer Disease. It covers the mechanisms of action, causes, and strategies for protecting the gastric mucosa. Test your knowledge of medications like Cimetidine and Omeprazole, and their roles in managing these conditions.

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