Drugs Affecting Acid Secretion

Question 1

What are the defensive factors of gastric mucosa?

Answer 1

Epithelial lining
Cell replication and restitution
Mucous membrane barrier
Vascular supply

Question 2

What are the aggressive factors of gastric mucosa?

Answer 2

Acid
Helicobacter pylori
Drugs

Question 3

What are the different targets of the parietal (oxyntic) cell?

Answer 3

Stimulatory receptors of the baso-lateral membrane

Proton pump (canalicular membrane)

Question 4

What are the different targets of the parietal (oxyntic) cell baso-lateral membrane?

Answer 4

Acetylcholine

Cholecystokinin B (CCK-B)

Histamine 2 receptor (H2)

Question 5

Tell me about PPI action.

Answer 5

Omeprazole, Lanosprazole, Esomeprazole

Targets ATPase
Acid-activated pro-drugs
Accumulate selectively in the acid space active drug
Binds covalently to cysteine’s of ATPase

Delayed action as not all pumps active all of the time
Max efficacy after 2-3 days
Restoration of acid secretion requires de novo synthesis

Question 6

Tell me about H2 receptor antagonists.

Answer 6

Ranitidine

Short half life
Twice daily

Question 7

Tell me about the treatment of peptic ulcers.

Answer 7

Normally caused by helicobacter pylori

Treated with antibiotics
Clarithromycin
Amoxycillin

And normally given a PPI as well

Other drugs used:
Antacids
- Rennies, Gaviscon

Alginates
- Sucralfate

Question 8

What are the principles of GORD treatment?

Answer 8

Symptom control

Healing of oesophagitis

Question 9

What are the different treatments in GORD symptom control?

Answer 9

Lifestyle
Antacids/alginates
H2 receptor antagonist
PPI