Drugs Affecting Acid Secretion

Question 1

What are we aiming to protect from when prescribing drugs that act on the stomach?

Answer 1

Helicobacter pylori
Acid
Drugs eg NSAIDs, Aspirin

Question 2

What defensive factors in the stomach do we target?

Answer 2

Mucus barrier
Vascular Supply
Acid production (↓)
Epithelial Integrity

Question 3

Which cells can be targetted to reduce acid production?

Answer 3

Parietal cells

Question 4

What receptors in parietal cells can be targetted? (3)

Answer 4

H2 histamine receptors **
M3 ACh receptors
CCK B receptors for gastrin

Question 5

Which is the most effective target for reducing acid secretion?

Answer 5

H2 histamine receptors

Question 6

Where are proton pumps located?

Answer 6

Canalicular membrane

Question 7

Which pump is targetted by PPIs?

Answer 7

H+-K+ ATPase exchanger

Question 8

Are proton pumps always active?

Answer 8

NO

Question 9

When do PPIs work?

Answer 9

When the pumps are active, i.e. take them before a meal

Question 10

Whichis the most potent PPI?

Answer 10

Omeprazole

Question 11

How quickly does omperazole work?

Answer 11

After 1 day

Question 12

When, generally speaking, are PPIs at their most effective?

Answer 12

2-3 days after taking

Question 13

How frequently should H2 antagonists be given? Why?

Answer 13

Twice a day as their t1/2 is short

Question 14

What are 25% of gastric ulcers caused by?

Answer 14

NSAIDs/Aspirin

Question 15

What are 75% of gastric ulcers caused by?

Answer 15

H. pylori

Question 16

What are 96% of duodenal ulcers caused by?

Answer 16

H. pylori

Question 17

What kind of scheme is used for treating peptic disorders?

Answer 17

A step up/down approach

Question 18

What is the first step in treating peptic disorders?

Answer 18

Antacids

Question 19

How do antacids work?

Answer 19

Bases within the antacids counteract the acid within the stomach to increase the pH

Question 20

Name some antacids

Answer 20

Alka-Seltzer
Milk of Magnesia
Pepto-Bismol
Tums

Question 21

What are the active ingredients in antacids?

Answer 21

aluminium hydroxide
magnesium carbonate
magnesium trisilicate
magnesium hydroxide
calcium carbonate
sodium bicarbonate

Question 22

What is the second step in treating peptic disorders?

Answer 22

Alginates

Question 23

How do alginates work?

Answer 23

Adhere to exposed or inflammed mucosa

Question 24

Name an alginate

Answer 24

Gaviscon

Question 25

What is the third step in treating peptic disorders?

Answer 25

H2RAs (H2 receptors antagonists)

Question 26

Name some H2RAs

Answer 26

Cimetidine Ranitidine Nizatidine Famotidine

Question 27

What is cimetidine metabolised by?

Answer 27

CYP450

Question 28

What is a specific ADR of cimetidine?

Answer 28

Gynaecomastia

Question 29

What is the main side effect of H2RAs?

Answer 29

Diarrhoea

Question 30

Are H2RAs generally safe and well tolerated?

Answer 30

Yes

Question 31

What is the fourth step in peptic disorder treatment?

Answer 31

PPIs

Question 32

Name some PPIs

Answer 32

``` Omeprazole Lansoprazole Rabeprazole Pantoprazole Esomeprazole ```

Question 33

What are the most common ADRs of PPIs?

Answer 33

Diarrhoea | Colitis

Question 34

What is a potential complication of long term use of PPIs?

Answer 34

Upregulation of G cells

Question 35

What should be the very first step, before therpaeutic intervention, in treating GORD?

Answer 35

Lifestyle modification

Question 36

What lifestyle modifications should be advised in GORD?

Answer 36

Avoid heavy meals Lose weight Decrease chocolate and alcohol intake

Question 37

What is a complications of oesophagitis?

Answer 37

Barrets Oesophagus

Question 38

How is Barrets oesophagus treated?

Answer 38

Life-long PPI therapy

Question 39

What should be stopped if a patient has peptic ulcers?

Answer 39

NSAIDs

Question 40

What can be used for a temporary fix/symptom relief in peptic ulceration, and how long for?

Answer 40

H2RA or PPI for 6 weeks

Question 41

What is usually the cure of peptic ulcers?

Answer 41

Eradicating H. pylori

Question 42

How is H. pylori eradicated?

Answer 42

A 7 day, twice daily course of a PPI and 2 antibiotics

Question 43

Which antibiotics are used (without a penicillin allergy) to treat H. pylori?

Answer 43

Amoxacillin and either clarithromycin or metronidazole

Question 44

How is H. pylori treated in patients with a penicillin allergy?

Answer 44

PPI + clarithromycin + metronidazole (unless had clarithromycin exposure before)

Question 45

What is the issue with eradiaction of H. pylori?

Answer 45

It is a hard regime to stick to even for 7 days, so compliance is essential to encourage otherwise it will come back