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Classification of Drugs Used in Acid-Peptic Disorders
This page provides an overview of the drugs used to manage acid-peptic disorders, covering their mechanisms of action, adverse effects, and contraindications.
1. Antacids
- Examples: Magnesium hydroxide, Aluminum hydroxide, Calcium carbonate
- Mechanism of Action: Neutralizes stomach acid by increasing pH, providing symptomatic relief.
- Adverse Effects:
- Magnesium-based: Diarrhea
- Aluminum-based: Constipation
- Calcium carbonate: Rebound hyperacidity
- Contraindications: Renal impairment (risk of hypermagnesemia or aluminum toxicity), hypercalcemia (for calcium-containing antacids).
2. H2 Receptor Antagonists
- Examples: Ranitidine, Famotidine, Cimetidine
- Mechanism of Action: Blocks H2 receptors on gastric parietal cells, reducing gastric acid secretion.
- Adverse Effects:
- Headache, dizziness, constipation
- Cimetidine may cause gynecomastia and impotence (antiandrogenic effects)
- Contraindications: Use cautiously in patients with renal or hepatic impairment.
3. Proton Pump Inhibitors (PPIs)
- Examples: Omeprazole, Pantoprazole, Esomeprazole
- Mechanism of Action: Irreversibly inhibits the H+/K+ ATPase enzyme in parietal cells, drastically reducing acid production.
- Adverse Effects:
- Headache, nausea, diarrhea
- Long-term use: Vitamin B12 deficiency, increased risk of fractures, Clostridium difficile infection
- Contraindications: Hypersensitivity to PPIs; caution in long-term use due to potential nutrient malabsorption.
4. Cytoprotective Agents
- Examples: Sucralfate, Misoprostol
- Mechanism of Action:
- Sucralfate: Forms a protective barrier over ulcers, shielding them from acid and pepsin.
- Misoprostol: A prostaglandin analog that increases mucus and bicarbonate secretion, protecting the gastric lining.
- Adverse Effects:
- Sucralfate: Constipation
- Misoprostol: Diarrhea, abdominal pain
- Contraindications:
- Misoprostol: Contraindicated in pregnancy (may induce uterine contractions and lead to miscarriage).
- Sucralfate: Caution in patients with renal failure (aluminum content).
5. Prokinetic Agents
- Examples: Metoclopramide, Domperidone
- Mechanism of Action: Enhances gastric emptying and improves esophageal sphincter tone, reducing reflux symptoms.
- Adverse Effects:
- Metoclopramide: Drowsiness, extrapyramidal symptoms (e.g., dystonia, tardive dyskinesia)
- Contraindications: Contraindicated in Parkinson’s disease (due to dopamine antagonism) and patients with GI obstruction.
6. Antibiotics (for H. pylori infection)
- Examples: Clarithromycin, Amoxicillin, Metronidazole
- Mechanism of Action: Eradicates Helicobacter pylori bacteria, reducing ulcer recurrence.
- Adverse Effects: Diarrhea, nausea, antibiotic resistance
- Contraindications: Hypersensitivity to specific antibiotics; caution in patients with hepatic impairment.
