20. Drugs For GORD

Question 1

Which 3 receptors can we target for preventing acid secretion? Which molecules bind to them?

Answer 1

1) M3 ACh receptors: ACh binds here
2) H2 histamine receptors: histamine binds here
3) CCK-B receptors: Gastrin binds here

Question 2

Where are ACh, Gastrin and histamine released from?

Answer 2

• ACh is released from enteric neurones
• gastrin is released from G cells
• histamine is released from enterochromaffin like cells (ECL) located in the gastric epithelium

Question 3

If we block (antagonise) 1 of the 3 receptors involved with acid production what will happen?

Answer 3

• we dont stop production from the other 2 therefore the patient will still produce acid
• usually give a H2 receptor antagonist

Note that if we block the final common pathway however you can stop acid production all together and you will get Achlorhydria/hypochlorhydria which is when the production of hydrochloride acid in gastric secretions of the stomach and other digestive organs is absent or low.

Question 4

How do proton pump inhibitors work?

Answer 4

• irreversibly bind to proton pumps
• but only active pumps - to be activated you need to eat food, and only 1/3 are active at 1 time
• max efficacy seen after 2-3 days so not good for PRN

Question 5

What is Helicobacter pylori infection?

Answer 5

• it is when H.Pylori infects your lower stomach (antrum) usually during childhood
• inflammation of the gastric mucosa
• this can lead to duodenal or gastric ulcers
• complications include bleeding and perforated ulcers

Question 6

How can we eradicate H pylori?

Answer 6

Need to give 2 types of antibiotic and 1 PPI. E.g.:

Clarithromycin 500mg BD
Amoxicillin 1mg BD
Lansoprazole 30mg BD

Patient must adhere and take treatment for a week otherwise may get recurrence. They may get diarrhoea however

Question 7

What are the 4 classes of medication we can use to target peptic disorders/GORD?

Answer 7

1) Antacids e.g. milk of magnesia. Relief for 1/2 hrs
2) alginates e.g. gaviscon
3) H2 receptor antagonists e.g. cimetidine, ranitidine
4) PPI e.g. omeprazole, lansoprazole

Question 8

Which population might we avoid cimetidine in and why?

Answer 8

Men

May cause gynaecomastia

Question 9

Why might PPIs lead to fractures?

Answer 9

• PPIs lead to a change in pH
• this can affect the uptake of calcium in the small bowel
• maybe more prone to osteoporosis and therefore fractures

Question 10

How is GORD managed?

Answer 10

• stopping NSAIDS
• not having a a spicy diet
• not drinking alcohol
• elevating bed/pillows
• exercise

Question 11

What is meant by the step up/step down management for GORD?

Answer 11

Step up usually used in GP i.e. start with lifestyle mods, and if no improvement progress to antacids/alginates, then H2RA, PPI.

Step down used in acute patients in hospital - start with a PPI and the step down.