Pharmacology of Antiulcer Agents

Pharmacology of Antiulcer Agents explains drugs that reduce gastric acid, protect mucosa, and promote healing of ulcers.

Pharmacology of Antiulcer Agents

• Antiulcer agents are drugs used to treat and prevent ulcers in the stomach and duodenum.
• These medications work by reducing stomach acid, protecting the stomach lining, or eliminating H. pylori

Classes of Antiulcer Drugs

1. Proton Pump Inhibitors (PPIs)

   • Examples: Omeprazole, Pantoprazole, Esomeprazole
   • Mechanism: Irreversibly inhibit H⁺/K⁺-ATPase (proton pump) in gastric parietal cells → ↓ acid secretion
   • Use: Peptic ulcer, GERD, pylori eradication (part of triple therapy)
   • Note: Most potent acid-suppressing agents

2. H₂-Receptor Antagonists

   • Examples: Ranitidine (withdrawn in many countries), Famotidine
   • Mechanism: Block H₂ receptors on parietal cells → ↓ acid secretion
   • Use: Mild ulcers, GERD
   • Note: Less potent than PPIs

3. Antacids

   • Examples: Aluminum hydroxide, Magnesium hydroxide, Calcium carbonate
   • Mechanism: Neutralize gastric acid → raise pH
   • Use: Symptomatic relief of heartburn, indigestion
   • Caution:
     • Magnesium salts → diarrhea
     • Aluminum salts → constipation

4. Mucosal Protective Agents

   • Sucralfate: Forms protective gel over ulcer
   • Bismuth compounds: Coats ulcer, has antimicrobial action
   • Misoprostol: Prostaglandin analog → ↑ mucus and bicarbonate, ↓ acid
     • Use: NSAID-induced ulcers
     • Contraindicated in pregnancy

5. Antibiotics for pylori

   • Examples: Clarithromycin, Amoxicillin, Metronidazole
   • Use: Used in triple therapy or quadruple therapy
   • Triple Therapy: PPI + Clarithromycin + Amoxicillin/Metronidazole

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