H2 antagonists Flashcards
1
Q
What are the generic and brand names of H2 antagonists?
A
- Ranitidine (Zantac)
* Cimetidine (Tagamet)
2
Q
What is the method of action of H2 antagonists
A
- Histamine is released by local paracrine cells
- Block H2 histamine receptors on parietal cells
- Reduces gastric acid output via the proton pump of the gastric parietal cells
3
Q
What are the indications for H2 antagonists?
A
- Gastro-oesophageal reflux disease
- Functional (ulcer) dyspepsia
- Mendelson’s syndrome – aspiration during anaesthesia causing pneumonitis
- Functional dyspepsia
- Healing of NSAID associated ulcers
- Prophylaxis for haemorrhage from duodenal ulcers
4
Q
What are the contraindications for H2 antagonists?
A
- Stomach cancer (or red flag symptoms that make you suspect stomach cancer)
- Liver problems
- Kidney problems
- Porphyria
5
Q
What are the side effects from H2 antagonists?
A
- Diarrhoea
- Headache
- Dizziness
- Rash
6
Q
What are the interactions with H2 antagonists?
A
- Warfarin – inhibits the cytochrome P450 system
- Benzodiazepines – ↑ absorption
- Imidazoles - ↓ absorption
7
Q
Through which organs are H2 antagonists eliminated?
A
- Hepatic
* Renal
