Gastritis & peptic ulcer

Question 1

What are the 3 agents used to reduce gastric acidity?

Answer 1

1. Antacids
2. H2-receptor antagonists
3. PPIs

Question 2

What are the 4 weak bases used in antacids?

Answer 2

NaHCO3
CaCO3
Mg(OH)2
Al(OH)3

Question 3

What benefit does simethicone have when taken with antacids?

Answer 3

Antifoaming activity coalesces bubbles and reduces bloating.

Helps to reduce gastric distention, belching discomfort side effects.

Question 4

In which patients is long-term antacid use contraindicated in?

Answer 4

Renal insufficiency
Patients on diuretics

Question 5

What type of antacid causes osmotic diarrhoea?

Answer 5

Mg2+ antacids

Question 6

What type of antacid causes constipation?

Answer 6

Al3+ antacids

Question 7

Which type of antacid is most prone to reboud acid secretion?

Answer 7

Ca2+

Question 8

Which types of antacids cause metabolic alkalosis/Milk-Alkali syndrome?

Answer 8

Na+ & Ca2+

Question 9

Name 3 H2-receptor antagonists

Answer 9

1. Famotidine
2. Ranitidine
3. Cimetidine

Question 10

What is the MOA of famotidine?

Answer 10

Competitive inhibitor of H2 receptors on parietal cells; suppresses acid secretion by parietal cells

Question 11

When is famotidine most effective?

Answer 11

At night

Noctornal acid secretion is mostly due to histamine release

Question 12

What are the common adverse effects of famotidine & ranitidine?

Think of muscarinic antagonism

Answer 12

Headache
Nausea
Dry mouth

Question 13

What are the severe adverse effects of famotidine & ranitidine?

Answer 13

Tachycardia
Blood dyscrasia
Blurred vision
MSK pain

blood dyscrasia - imbalance of blood cell types

Question 14

What are the severe adverse effects of cimetidine?

Answer 14

Mental confusion

Anti-androgenic, inhibits estradiol metabolism, increases serum prolactin
gynaecomastia, impotence, glaactorrhoea

Question 15

What is the MOA of omeprazole?

Answer 15

Irreversibly inhibits H+/K+-ATPase in parietal cells

IRREVERSIBLE!!!

Question 16

What is the main function of the enteric coating around omeprazole?

Answer 16

Protects against early activation by stomach acidicity

Question 17

Why must early activation of omeprazole be avoided?

Answer 17

Activated omeprazole has poor bioavailability; will not be absorbed by the intestines and delivered to the parietal cells via the blood

Question 18

What is the DOA of omeprazole?

Answer 18

24H

IRREVERSIBLE INHIBITION OF PROTON PUMP

Question 19

When should omeprazole be given?

Answer 19

1H before food

Proton pumps must be present and active before omeprazole can exert its effect

Question 20

What are the common adverse effects of PPIs?

Answer 20

Headache
Nausea
Dizziness
Diarrhoea
Flatulence
Rash

Question 21

What are the severe adverse effects of PPIs?

Answer 21

Increased risk of C. diff, MDR organism infections
Hypomagnesaemia
Microscopic colitis
Lupus
Kidney disease

MDR - multi-drug resistant

Question 22

What are the 3 cytoprotective agents?

Answer 22

1. Sucralfate
2. Bismuth compounds
3. Misoprostol

Question 23

What is the MOA of sucralfate?

Answer 23

1. Breaksdown into sucrose sulphate (strong -ve charge) –> binds to +ve charged proteins at ulcer crater –> forms viscous, tenacious gel that prevents further acid attack
2. Stimulates mucosal prostaglandins

Question 24

When should sucralfate be administered?

Answer 24

1H before meals

Question 25

What are the adverse effects of sucralfate? ## Footnote Hint - contains Al3+

Answer 25

Constipation Impairs absorption of other drugs ## Footnote Binds to other drugs preventing absorption

Question 26

What is the MOA of bismuth compounds?

Answer 26

1. Forms a protective layer protecting ulcers from acid & pepsin 2. Stimulates mucus & HCO3- secretion

Question 27

What 2 drugs have weak anti-microbial activity against H. pylori?

Answer 27

Omeprazole Bismuth compounds

Question 28

What drug is assosciated with darkening of tongue & blackening of stools?

Answer 28

Bismuth compounds

Question 29

What are the servere adverse effects of bismuth compounds?

Answer 29

Encephalopathy

Question 30

What group of patients is bismuth use contraindicated in?

Answer 30

Renal insufficiency

Question 31

What is the MOA of misoprostol?

Answer 31

Synthetic PGE1 analogue that binds to PGE2 receptors, mimicking the gastric protective effects of prostaglandins ## Footnote Increase HCO3- & mucus sevretion, increase mucosal blood flow, decrease gastric acid secretion

Question 32

What are the adverse effects of misoprostol? ## Footnote Hint - BAAD

Answer 32

Bone pain Abortion Abdominal pain Diarrhoea

Question 33

What is the triple therapy for H. pylori infection?

Answer 33

Clarithromycin Amoxicillin or Metronidazole PPI

Question 34

Why is double antibiotic therapy required when treating H. pylori?

Answer 34

H. pylori becomes resistant to metronidazole & clarithromycin when given alone

Question 35

If triple therapy does not work for H. pylori infection, what is the second line treatment?

Answer 35

Add bismuth compound

Question 36

Why is PPI given alongside double antibiotic therapy during H. pylori infection?

Answer 36

1. Reduce symptoms of peptic ulcer disease & allow for healing 2. **Makes antibiotics more effective**