GI Pharmacology

Question 1

What are the drug groups used for acid suppression?

Answer 1

Antacids
Alginates
H2 antagonists
PPIs

Question 2

What is an example of an antacid?

Answer 2

Maalox (aluminium + magnesium)
Rennie (calcium)

Question 3

How do antacids work?

Answer 3

Neutralise stomach acids by the active base reacting with the acid

Question 4

What is an example of an alginate?

Answer 4

Gaviscon

Question 5

How do alginates work?

Answer 5

Alginate forms a gel like raft that sits on top of stomach contents

Question 6

What is an example of a H2 antagonist?

Answer 6

Ranitidine

Question 7

How do H2 antagonists work?

Answer 7

Block H2 histamine receptors stopping influx of hydrogen into intestinal lumen

Question 8

When are H2 antagonists indicated?

Answer 8

Gastric ulcers
GORD
Dyspepsia

Question 9

What is an example of a PPI?

Answer 9

Omeprazole
Lansoprazole

Question 10

How do PPI’s work?

Answer 10

Inhibit H+/K+ ATPase proton pump to reduce acid secretion

Question 11

When are PPIs indicated?

Answer 11

Gastric ulcers
GORD
Dyspepsia
H. pylori eradication

Question 12

What are the drug groups used for nausea and vomiting?

Answer 12

Antiemetics

Question 13

What drugs are used against the Chemoreceptor Trigger Zone (CRTZ)?

Answer 13

D2 (dopamine) receptors- haloperidol
5HT3 receptors- ondansetron

Question 14

What drugs are used against the vomiting centre?

Answer 14

5HT2 receptors- levomepromazine
H1 histamine receptor- cyclizine, levomepromazine
ACH muscarinic receptor- cylcizine, levomepromazine

Question 15

What drugs are used against the gut?

Answer 15

5HT4 agonist- metoclopramide
DT agonist- metoclopramide
Motilin- macrolide antibiotic

Question 16

What are the drug groups used for GI motility?

Answer 16

Antispasmodics
Antidiarrheal
Laxatives

Question 17

What is the function of antispasmodics?

Answer 17

Muscle relaxation

Question 18

What are the 2 types of antispasmodics?

Answer 18

Antimuscarinics- Buscopan
Calcium channel blockers- peppermint oil

Question 19

What is the function of antidiarrheals?

Answer 19

Slow down gut motility

Question 20

What are the types of antidiarrheals

Answer 20

Opioids:
- Loperamide
- Codeine
- Morphine

Question 21

What are the 4 types of laxatives?

Answer 21

Bulk forming- isphagula
Stool softeners- docusate
Osmotic laxatives- lactulose
Stimulant laxatives- bisacodyl

Question 22

How do bulk forming laxatives work?

Answer 22

Increase bulk of stool which stimulates stretch receptors increasing peristalsis

Question 23

How do stool softeners work?

Answer 23

Incorporate more water into stool

Question 24

How do osmotic laxatives work?

Answer 24

Act as solutes in the fluid in the gut. Sets up concentration gradient for more water to stay in bowel

Question 25

How do stimulant laxatives work?

Answer 25

Irritate bowel to stimulate it to increase peristalsis

Question 26

What are the drug groups used for IBD treatment?

Answer 26

1. Aminosalicylates 2. Corticosteroids 3. Immunosuppressants 4. Biologics

Question 27

What is an example of an aminosalicylate?

Answer 27

Mesalazine

Question 28

What is the function of Aminosalicylates?

Answer 28

Induction and remission of UC

Question 29

What is an example of a corticosteroid?

Answer 29

Prednisilone Budseonide

Question 30

What are the side effects of CORTICOSTEROIDs?

Answer 30

- **C**ushing syndrome - **O**steoporosis - **R**educed growth - **T**hin skin - **I**mmunosuppression - **C**ataracts - **O**edema - **S**uppressed HP axis (foetal development) - **T**eratogenic - **E**motional disturbance - **R**ise in BP - **O**besity - **I**ncreased hair growth - **D**iabetes

Question 31

What is the function of corticosteroids?

Answer 31

Induction of remission in UC and CD

Question 32

What is an example of an immunosuppressant?

Answer 32

Azathioprine -> 6-mecaptopurine

Question 33

What are the 2 methods of action of biologics?

Answer 33

Block cytokines Block recruitments of WBCs

Question 34

What biologics block cytokines?

Answer 34

Anti TNFa- Infliximab Anti IL-12/23- Ustekinumab

Question 35

What biologics block recruitment of WBCs?

Answer 35

Anti-integrin Vendolizumab

Question 36

What are the drug groups used for biliary secretions?

Answer 36

Bile acid sequestrants Bile acid drugs

Question 37

What is an example of a bile acid sequestrant?

Answer 37

Cholestyramine

Question 38

What is the indication for bile acid sequestrants?

Answer 38

Pruritis from a biliary cause

Question 39

What is an example of a bile drug?

Answer 39

Ursodeoxycholic acid

Question 40

How does ursodeoxycholic acid work?

Answer 40

Inibits enzyme involved in formation of cholesterol and therefore restores the ratio of cholesterol to bile salts so non-calcified gallstones will slowly dissolve

Question 41

What is the indication for ursodeoxycholic acid?

Answer 41

Non calcified gall stones Primary biliary cirrhosis