GI: H2 RECEPTOR AGONISTS

Question 1

H2RA: INDICATIONS

Answer 1

• Gord

- Dyspepsia

Question 2

H2RA: MOA

Answer 2

• Reduce GASTRIC ACID SECRETION
  [Stomach GASTRIC Parietal cells produce acid, via exchange of H+/K via a PROTON PUMP+. H+ pumped out into the lumen of the stomach, whilst the transporter takes a K+ into the cell in exchange. The proton pump is regulated by HISTAMINE which is excreted by local paracrine cells and binds to H2 receptors on the gastric parietal cell]
• Blocking H2 receptors can decrease gastric acid secretion, however the PP can be stimulated in other ways -> therefore the H2 blockers cannot completely suppress gastric acid production

Question 3

H2RA: ADVERSE EFFECTS

Answer 3

• Well tolerated, with few side effects
• Bowel disturbance
• Headache
• Dizziness

Question 4

H2RA: WARNINGS

Answer 4

• Excreted in the kidneys, so their dose should be reduced in patients with renal impairment
• Like PPIs, can disguise the the symptoms of gastric cancer -> Don’t just tx symptoms, consider the cause

Question 5

H2RA: INTERACTIONS

Answer 5

• No major drug interactions

Question 6

H2RA: EXAMPLES

Answer 6

• Ranitidine