Gastrointestinal: SMP Pharmacology

Question 1

What substances produced by the stomach are the “attackers” of gut mucosa via stimulation of acid secretion?

Answer 1

Stimulate acid secretion:

• Histamine
• Gastrin
• ACh

Question 2

What substances are “defenders” of gut mucosa?

Answer 2

Somatostatin and Prostaglandins through stimulation of:

• Mucus secretion
• Bicarbonate ion secretion
• Blood flow

Question 3

What do gastric chief cells secrete?

Answer 3

Pepsinogen → pepsin (a protease)

Question 4

What do gastric parietal cells secrete?

Answer 4

Hydrochloric acid

Question 5

What substances (3) stimulate the secretion of hydrochloric acid?

Answer 5

• Gastrin: peptide hormone of the stomach
• ACh: parasympathetic neurotransmitter released from the vagus nerve
• Histamine: local mediator

Question 6

What is the parasympathetic neurotransmitter released from the vagus nerve?

Answer 6

ACh

Question 7

What is the broad action of antacids like aluminim hydroxide?

Answer 7

Neutralise acid secretion

Question 8

What is the broad action of histamine H2 receptor antagonists (blockers) like ranitidine?

Answer 8

Inhibit acid secretion

Question 9

What is the broad action of proton pump inhibitors like omeprazole?

Answer 9

Inhibit acid secretion

Question 10

What class of drug is aluminium hydroxide?

Answer 10

Antacid

Question 11

What class of drug is Ranitidine?

Answer 11

Histamine H2 receptor antagonist (blocker)

Question 12

What class of drug is Ameprazole?

Answer 12

Proton pump inhibitor (PPI)

Question 13

What is the drug treatment of Helicobacter Pylori?

Answer 13

Triple therapy:

• Proton pump inhibitor (PPI)
• Amoxycillin (or metronidazole)
• Clarithromycin

Question 14

What class of drug is Magnesium hydroxide?

Answer 14

Antacid

Question 16

What class of drug is Famotidine?

Answer 16

Histamine H2 receptor antagonist (blocker)

Question 17

What class of drug is Nizatidine?

Answer 17

Histamine H2 receptor antagonist (blocker)

Question 18

What is the action of antacid drugs (3)?

Answer 18

• Neutralises acid
• Raises pH to ~5
• Inhibits peptic activity

Question 19

What is the mechanism of action of histamine H2 receptor antagonists?

Answer 19

• Comptetitively inhibit actions of histamine
• Reduce histamine, gastrin and ACh stimulated acid secretion by 90%

Question 20

What class of drug is espmeprazole?

Answer 20

Proton pump inhibitor

Question 21

What class of drug is pantoprazole?

Answer 21

Proton pump inhibitor

Question 22

What class of drug is rabeprazole?

Answer 22

Proton pump inhibitor

Question 23

What is the mechanism of action of proton pump inhibitors?

Answer 23

• Irreversible inhibition of the H+/K+ ATPase (proton pump)
• Markedly inhibit acid secretion

Question 24

What is the potential side effect caused by magnesium salts in antacids?

Answer 24

Diarrhoea

Question 25

What is the potential **side effect** caused by **aluminium salts in antacids**?

Answer 25

Constipation

Question 26

What are (5) common **side effects** of **proton pump inhibitors**?

Answer 26

* Headache * Nausea * Diarrhoea * Fatigue * Dizziness

Question 27

What class of drug is **Diphenhydramine**?