Common drugs in GORD/PUD Flashcards
What are the main receptors associated with a parietal cell?
Proton pump
H2 receptor
M3 receptor
CCK2 receptor
Prostaglandin receptor
List four protective substances in the stomach
Mucus
Bicarbonate
Prostaglandins
Mucosal blood flow
List four aggressive substances in the stomach
Acid
Pepsins
NSAIDs
H. pylori
What is the role of antacids?
To neutralise acid produced in the stomach
What is the role of alginates?
Increase viscosity of stomach content
Some form a “raft” to reduce symptoms of reflux
Give examples of antacids
Sodium Bicarbonate
Magnesium and Aluminium salts
Gaviscon
Rennie
Simeticone
Give an example of an alginate
Sodium alginate
What is the side effect of aluminium?
Constipation
What is the side of effect of magnesium?
Diarrhoea
What do alginates and antacids interact with?
Some antibiotics , i.e. coprofloxacin, tetracycline
Enteric coated preperations
What is the mechanism of action of sulcralfate?
Protect damaged mucosa by stimulating local production of prostaglandins and bicarbonate
What are the infications of sucralfate?
Treatment of peptic ulceration
Prophylaxis of stress ulceration
What are the side effects of sucralfate?
Constipation
What does sucralfate interact with?
Enteral feeds - “bezoar” formation
Digoxin, antibiotics, phenytoin - reduced absorption
What is the mechanism of action of misoprostol?
Prostaglandin analoge, i.e. prostaglandin receptor agonist
used in combination with NSAID, e.g. arthrotec
What are the side effects of misoprostol?
Diarrhoea and abdominal pain
What are the contraindications of misoprostol?
Pregnant women / Women of child-bearing age
Give examples of gastric stimulants
Domperidone
Metoclopramide
What is the mechanism of action of gastric stimulants?
Increases peristalisis in duodenum and jejunum, thought to be due to stimulation of muscarinic receptors in GIT
Give examples of H2-receptor antagonists
Ranitidine
Nizatidine
Famotidine
Cimetidine
What are H2-receptor antagonists mechanism of action?
Reversibly and competitively bind to H2-receptor
- suppresses gastric acid secretion
- inhibits gastrin and ACh-mediated acid secretion
What are the indications of H2-receptor antagonists?
PUD
GORD symptoms
HIgh dose in ZE syndrome
How are H2-receptor antagonists excreted?
Renal and hepatic excretion
- important to know in case of renal/hepatic impairment
What are the side effects of H2-receptor antagonists?
Diarrhoea/constipation
Headache
Confusion
Hallucinations
How does Cimetidine affect the cytochrome-p450 system?
Inhibits it
Give examples of PPIs?
Omeprazole
Lanzaprazole
Pantoprazole
Esomeprazole
What are the indications of PPI?
PUD
Prevention and treatment of NSAID induced ulceration
Eradication of H.pylori (with Abx)
Severe GORD symptoms
Oesophagitis
ZE syndrome
Prevention of stress ulceration in critical care patients
What are the side effects of PPI?
No obvious ones
Rare: rash, headache, diarrhoea, nausea
List any interactions of PPIs?
Omeprazole with clopidogrel
What are some of the functions of prostaglandins?
Protection of gastric mucosa
Platelet function
Pain, inflamamtion and fever
Renal homeostasis
