Medicine Quiz: Peptic Ulcer and Gastroesophageal Reflux Disease

Gastrointestinal Disorders and Treatments

• Peptic ulcers occur in the stomach and duodenum, often resulting from an imbalance between aggressive (acid) and defensive (mucosa) factors.
• Two types of peptic ulcers: gastric ulcers and duodenal ulcers (most common).
• Acid secretion in the stomach is initiated by activation of the H+/K+-ATPase pump, influenced by histamine (H2), gastrin (CCK2), and acetylcholine (M1 and M3).

Treatment Options for Peptic Ulcers

• Proton Pump Inhibitors (PPIs):

  • Inhibit H+/K+-ATPase and neutralize stomach acidity.
  • Administered orally (30 minutes before meals) or intravenously for certain PPIs.
  • Long duration of action despite short half-life (1.5 hours) due to "hit and run" mechanism.
  • Lansoprazole is considered most potent and safest for pregnancy; rabeprazole is the longest acting.

• H2 Receptor Blockers:

  • Block H2 receptors to reduce acid secretion.
  • Common drugs include cimetidine (prototype), ranitidine, famotidine, and roxatidine.
  • Less potent than PPIs; may lead to drug interactions, especially with enteric coated naproxen.

• Antacids:

  • Provide rapid relief from acidity; include systemic (e.g., sodium bicarbonate) and non-systemic options (e.g., aluminum hydroxide, magnesium hydroxide).
  • Can alter drug absorption, affecting medications like tetracyclines and ketoconazole.

• Cytoprotective Agents:

  • Prostaglandin analogues (e.g., misoprostol) protect the gastric lining and reduce acid secretion.
  • Ulcer protective drugs like sucralfate form a barrier over ulcers, protecting against stomach acid.

Specific Agents and Their Properties

• Cimetidine:

  • Less potent and an enzyme inhibitor with antiandrogenic side effects.
  • Category B drug for pregnancy, implying safety.

• Carbenoxolone:

  • Steroidal agent from liquorice root, increases mucus production and can cause water retention.

• Colloidal Bismuth Subcitrate:

  • Enhances gastric mucosal defenses and may coat ulcer bases but can lead to discoloration of stool and tongue.

Gastroesophageal Reflux Disease (GERD)

• Commonly presents as heartburn; caused by stomach acid reflux into the esophagus.
• Treatment involves decreasing acid secretion or enhancing gastrointestinal motility.
• Drugs used include PPIs, H2 blockers, prokinetic agents, and antacids.

Emetics and Anti-Emetics

• Nausea and vomiting serve as protective reflexes against toxins in the gastrointestinal tract.
• The vomiting center in the medulla oblongata is stimulated by drugs such as apomorphine or external factors like mustard and salt.

This quiz covers different types of peptic ulcers, including GERD, NSAID-induced ulcers, and Zollinger-Ellison syndrome, as well as treatments such as PPIs, H2 blockers, and their mechanisms of action.