H2 antagonists Flashcards
1
Q
What are some examples of H2-receptor antagonists + what do they do
A
Ranitidine, cimetidine, famotidine
- reduce stomach acid secretion + allow for ulcer healing (less useful for food related acid secretion)
2
Q
What are the indications of use for H2 antagonists
A
- gastric or duodenal (PEPTIC) ulcers
- NSAID related ulcers
- dyspepsia
- GORD
3
Q
What is the mechanism of action in H2-receptor antagonists
A
- Histamine H2- receptor antagonist REDUCE GASTRIC ACID SECRETION
- Histamine regulated H+/K+ proton pump produces acid in parietal cells
- Blocking histamine interaction w/ receptor reduces pump action
- however pump also stimulated by other pathway so cannot completely suppress acid secretion
4
Q
What are the side effects
A
- generally well tolerated
- diarrhoea, headache, dizziness, fatigue
- Rash (ERYTHEMA MULTIFORME - target)
5
Q
What do you need to be careful with
A
- can disguise symptoms of gastric cancer
6
Q
What are the contraindications
A
- Renal impairment - Excreted by kidneys so lower dose
7
Q
What are the interactions
A
CYP450 inhibitor
8
Q
What are some useful notes
A
- Ranitidine has fewer side effects than cimetidine
- PPIs more effective
- Use PPI in pregnancy
