GORD

Question 1

H2-antagonists (ranitidine, cimetidine, femotidine)

Common indications

Answer 1

1. Gastric and duodenal ulcers
2. Chronic episodic dyspepsia
3. NSAID-associated ulceration
4. Prophylaxis of NSAID ulcers
5. GORD
6. Reduction of gastric acid prior to surgery (Prophylaxis of acid aspiration)

Question 2

H2 antagonist

MOA

Answer 2

• Inhibit the potentiation by histamine of the response to ACh and gastrin
• Parietal cells have 3 different receptors which stimulate acid secretion (H2, Muscarinic M3, gastrin receptor CCKb)
• Ranitidine binds to H2 receptor this means that the signal can not be potentiated even if one of the other receptors are stimulated
• Histamine is released by ECL cells

Question 3

H2 antagonists

Adverse effects

Answer 3

• Few common side effects: Mainly GI disturbances (constipation, diarrhoea)
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Question 4

H2 antagonist

Warnings

Answer 4

• Gastric cancer- Ranitidine can mask the symptoms of gastric cancer. Watch out for alarm symptoms (particularly OTC) e.g. unexplained weight loss