Excess Gastric Acid

Question 1

Does acetylcholine increase or decrease gastric acid secretion?

Answer 1

Increase

Question 2

What is the effect of somatostatin and prostaglandin on acid secretion?

Answer 2

Decrease

Question 3

Describe GORD and what typically causes it (anatomically)

Answer 3

Gastro-esophageal reflux disease. Involves reflux more than twice a week.
Caused by a weakened gastro-esophageal sphincter

Question 4

What are some of the symptoms of PUD?

Answer 4

Heart burn, nausea, reflux, vomiting

Epigastric pain

Question 5

Other than H. pylori, what else can cause gastric ulcers to form?

Answer 5

Stress, NSAIDs, gastric hyperactivity, smoking, alcohol

Question 6

Antacids neutralise the acid in the stomach, causing symptomatic relief. The most common salts in antacids are —- and —-. Name their common side effects.

Answer 6

Magnesium - diarrhoea

Aluminium - constipation

Question 7

Sucralfate, a mucosal protection agent, works by…..

Answer 7

Forming a thick viscous gel with the mucus in stomach. Coats the ulcer base, though might effect absorption of other substances / drugs

Question 8

Bismuth subsalicylate, a mucosal protective agent, has 3 MOAs. Name them.

Answer 8

1. Anti-secretory
2. Anti-inflammatory (inhibits prostaglandin synthesis)
3. Anti-bacterial (blocks the adhesions of bacteria to the epithelial layer)

Question 9

Misoprostol, a prostaglandin analogue, is commonly co-dosed with continuous NSAID dosing in elderly because it….

Answer 9

Directly suppresses the secretion of gastric acid, protecting the GIT from harmful acidic environment.

Question 10

H2 receptor antagonists, though no longer used, were used for GORD. What was the MOA

Answer 10

Antagonised H2 receptor on parietal cells, which are responsible for acid secretion.

Question 11

What is a common characteristic of PPIs?

Answer 11

Suffix -azole

Question 12

How do PPIs work? How long do their effects last for?

Answer 12

Work by irreversibly binding to proton pump. PPIs are weak bases, only activated when the reach the acidic environment of the stomach. They then covalently bond to the pump via a disulphide bond.
Effects last for 24-48 hrs until the cell is regenerated

Question 13

How to prokinetics provide relief in GORD? Examples?

Answer 13

They increase the rate of gastric emptying, meaning there is less pressure of on the sphincter. Only useful for GORD, not ulcers.
Examples = metoclopramide or domperidone

Question 14

How does the urea breath test work for H pylori detection?

Answer 14

Patients swallow C13 or 14, a radioactive isotope. Infected patients will release carbon dioxide.

Question 15

Other than breath test, how else can H pylori be detected?

Answer 15

Fecal antigen test, blood test (cannot distinguish between past and current infections), endoscopy or biopsy (invasive)

Question 16

What is triple therapy for h pylori eradication?

Answer 16

2 antibiotics + omeprazole (or h2 antagonist)

One of the antibiotics = clarithromyocin