What are peptic ulcers?
Describe a pathway by which HCL is secreted into the lumen of the stomach (1)
Describe a pathway by which HCL is secreted into the lumen of the stomach (2)
Describe a pathway by which HCL is secreted into the lumen of the stomach (3)
What is a PPI?
How does it work?
H+/K+ ATPase inhibitors/Proton Pump Inhibitors
It irreversibly destroys the proton pump
Therefore it decreases gastric acid secretion
What are the PPIs you need to know?
What is a Histamine H2 antagonist?
How does it work?
Inhibits histamine from binding to H2 receptor on parietal cell
thus parietal cell cannot releas gastric acid (HCl)
What Histamine H2 antagonist do you need to know?
Ranitidine (Zantac – main one used)
What is better H2 antagonist or PPI?
PPIs
What is the treatment for H. pylori?
Must eradicate H pylori to make ulcer doesn’t return. Therefore use PPI & amoxicillin & clarithromycin
How do antacids work?
• neutralize gastric acid
What are the side effects of the components of antacids?
Why are antacids used, what are the drawbacks of its use?
How do muscurinic receptor antagonists work?
i. Muscarinic receptor antagonist block ACh (normally increases motility)
What is an muscurinic antagonist spasmolytic?
• hyoscine butylbromide (Buscopan)
What are the direct spasmolytics and how do they act?
Direct spasmolytic (act directly on SM to relax it) = mebeverine, peppermint oil
How do PGE analogues work?
When are PGE contraindicated?
* ↑ uterine contractions (don’t use in pregnant women)
What is the name of a PGE analogue?
• Misoprostol
What is the Chemoreceptor trigger zone (CTZ)
The CTZ is located in the medulla outside the blood brain barrier. It communicates with other structures in the vomiting centre to initiate vomiting.
As a result of its position outside of the BBB it is sensative to toxins, bacteria, drugs
Name a H1 receptor antagonist?
Promethazine
Where does promethazine act?
In the gut - it does not enter the CNS
What is a side effect of H1 receptor antagonists?
Sedative
Name a muscurinic receptor antagonist?
Hyoscine hydrobromide