Prescribing - Gastroenterology Flashcards
What is Rantidine’s drug class?
H2 receptor antagonist
How does Ranitidine work?
reduces stimulation of gastric acid secretion
What are common side effects of Ranitidine?
Diarrhoea
Headache
Dizziness
When is Ranitidine contraindicated?
Hepatic or renal impairment requires dose reduction
Avoided in Pregnancy
In patients with red flags for gastric cancer- only prescribe if ruled out.
What is Cimetidine ?
H2 receptor antagonist
What is an important side affect of Cimetidine?
Gynaecomastia
What is an absolute contraindication of Cimetidine?
If on Warfrin, theophylline or phenytoin as cimetidine is a Cytochrome P450 inhibitor
What is Omeprazole?
A PPI
How does Omeprazole work?
inhibits final transport of hydrogen ions into the gastric lumen meaning less acid is secreted
What is the follow up for Omeprazole?
Prescribe at lowest effective dose for shortest period of time possible. If needed long term periodic reviews need to be had (every 8 weeks or so)
Magnesium levels need to be monitored
What are cautions of PPIs?
PPIs may mask symptoms of gastric cancer – in patients presenting with ‘alarm features’ (bleeding, dysphagia, recurrent vomiting, weight loss) it is important to rule out malignancy before commencing PPI therapy.
What drug interactions occur with Omeprazole?
Warfarin - increase anticoagulant effect)
Clopidogrel - may reduce antiplatelet effect)
What drug class is Loperamide?
Antimotility
How does loperamide work?
Is an agonist to the opioid mu receptors in the myenteric plexus of the large intestine. This reduces the tone in the large intestine muscles inhibiting peristalsis slowing motility
What are side effects of Loperamide
Abdominal cramps Dizziness Flatulence Headaches Nausea
Paralytic ileus!!!