H2-receptor antagonist

Question 1

What are indications for H2 antagonists?

Answer 1

• Peptic ulcer disease
• GORD
• Dyspepsia

Question 2

What is an example of of an H2 antagonist?

Answer 2

Ranitidine

Question 3

What is the mechanism of action of H2 antagonists?

Answer 3

Reduce gastric acid secretion by blocking histamine action on H2 receptors on gastric parietal cells.

Question 4

Why can H2 receptor antagonists not fully suppress acid production?

Answer 4

Other receptors are involed in stimulation of gastric acid secretion

Question 5

What are the most common side effects of H2 receptor antagonists?

Answer 5

• Diarrhoea/constipation
• Headache
• Dizziness

Question 6

How is acid secreted into the stomach?

Answer 6

By proton pump in gastric parietal cells, which secrete H+ into the stomach lumen in exchange for K+

Question 7

How are H2 receptor blockers excreted?

Answer 7

By the kidneys

Question 8

What can H2 antagonists disguise the presence of?

Answer 8

Gastric cancer

Question 9

When are oral preparations of ranitidine best taken?

Answer 9

Before, with or after food