Dyspepsia

Question 1

H2- receptor antagonist

Common indications

Answer 1

1. Peptic ulcer disease- for treatment and prevention of gastric and duodenal ulcers and NSAID-associated ulcers, although PPI are more effective and therefore usually preferred
2. GORD and dyspepsia- for releif of symptoms. PPIs are the main alternative and are preffered in more severe cases

Question 2

H2- receptor antagonist

MOA

Answer 2

• Histamine H2-antagonists reduce gastric acid secretion
• Acid in normally produced by the proton pump of the gastric parietal cells, which secretes H+ into the stomach lumen in exchange for K+
• Proton pump is regulated by histamine which stimulates the parietal cell via secondary messenger system
• However PP can be stimulated in many ways so H2-antagonists only give a partial blockage of secretions

Question 3

H2- receptor antagonist

Important adverse effects

Answer 3

• H2 blockers are well tolerate
• Common side effects: Bowel disturbances (Diarrhoea/constipation), headache and dizziness

Question 4

H2- receptor antagonist

Warnings

Answer 4

• H2-blockers are excreted by the kidneys so dose reduction is required in renal impairment
• They can disguise the symptoms of gastric cancer
  
  • Notice alarm symptoms- weight loss, swallowing difficulties)

Question 5

Proton Pump Inhibitors (PPIs)

Common indications

Answer 5

1. Prevention and treatment of peptic ulcer disesase- including NSAID-associated
2. Symptomatic relief of GORD + Dyspepsia
3. Eradication of H.pylori infection when used with combination antibiotic therapy

Question 6

Proton Pump Inhibitors (PPIs)

MOA

Answer 6

• PPIs reduce gastric acid secretion
• They act by irreversibly inhibiting H+/K+/ATPase pump is gastric parietal cells
• An advantage at targeting the final stage of gastric acid production is that they offer almost complete supression is acid production (compared to partial in H2-antagonists)

Question 7

Proton Pump Inhibitors (PPIs)

Important adverse effects

Answer 7

• GI disturbances
• Headache
• Increased risk of C.diff infection
• Hypomagnesaemia- this is linked to hypokalaemia and therefore arrhythmias and tetany

Question 8

Proton Pump Inhibitors (PPIs)

Warnings

Answer 8

• PPIs like H2-antagonists can mask the symptoms of gastric cancer
• Increased risk of fracture and oesteoporosis particularly in the elderly

Question 9

Proton Pump Inhibitors (PPIs)

Interactions

Answer 9

• There is some evidence that PPIs decrease the antiplatelet effect of clopidogrel by decreasing activation by CYP enzymes
• Lansoprazole and pantoprazole have a lower propensity for this interaction