Pharmacology

Question 1

What are the functions of prostaglandins in the stomach?

Answer 1

Reduce acid secretion
Increase mucus and bicarbonate secretion
Increase mucosal blood flow

Question 2

Why do NSAID’s cause peptic ulcers?

Answer 2

They reduce prostaglandin formation (COX1 inhibition)

Question 3

What can prevent gastric damage due to long term NSAI use?

Answer 3

Stable PGE1 analogue (e.g. misoprostol)

Question 4

How do PGE1 inhibitors prevent gastric damage by NSAID’s?

Answer 4

Inhibit basal and food-stimulated gastric acid formation

Maintain or increase secretion of mucus and bicarbonate

Question 5

What chronic infection of the gastric Antrum is associated with peptic ulcers?

Answer 5

H. pylori

Question 6

How does H. Pylori cause peptic ulcers?

Answer 6

H. Pylori protect in mucus gel causes a persistent inflammation that weakens the mucosal barrier
When the barrier breaks down leaves the submucosa open to attack from HCl and pepsin

Question 7

What are the aims of treatment of peptic ulcers?

Answer 7

Reduce acid secretion
Increase mucosal resistance
Eradicate H. pylori

Question 8

What conditions require drugs that reduce gastric acid secretion?

Answer 8

Peptic ulcer
GORD
Acid hypersecretion (e.g. Zollinger-Ellison syndrome, Cushing’s ulcers)

Question 9

Example of PPI

Answer 9

Omeprazole

Lansoprazole

Question 10

What is the mechanism of action of PPI’s

Answer 10

Inhibit active proton pumps

Not pumps in tubulovesicles

Question 11

Why is the timing of PPI dosing important?

Answer 11

Must present in plasma whilst proton pumps are active

Question 12

Side effects of PPI’s

Answer 12

Headache 
Diarrhoea/constipation 
Abdominal pain 
Flatulence 
Nausea 
Rash

Question 13

Examples of Histamine (H2) receptor antagonists

Answer 13

Ranitidine

Cimetidine

Question 14

What is the mechanism of action of H2 receptor antagonists?

Answer 14

Completely block histamine-mediated component of acid secretion and reduce secretion evoked by gastrin and ACh

Question 15

Side effects of H2 receptor antagonists

Answer 15

Diarrhoea 
Headache 
Dizziness 
Rash 
Tiredness

Question 16

Example of muscarinic ACh receptor antagonists

Answer 16

Pirezepine

Question 17

Example of mucosal strengtheners

Answer 17

Sucralfate

Bismuth chealate

Question 18

What is the mechanism of action of mucosal strengtheners?

Answer 18

Bind to ulcer base (+ve charged) and forms complex gels with mucus - provides mucosal barrier against HCL and pepsin

Also increases mucosal blood flow, mucus, bicarbonate and prostaglandin production

Question 19

What class of drugs can cause peptic ulcers?

Answer 19

NSAID’s

Question 20

What are purgatives?

Answer 20

Agents that cause purging or cleansing of the bowels by promoting evacuation

Question 21

When should neither laxatives or purgatives be used?

Answer 21

Physical obstruction to the bowel

Question 22

What to laxatives do?

Answer 22

Increase perostalsis and soften faeces assisting evacuation

Question 23

When are laxatives to be used?

Answer 23

If ‘straining is potentially damaging to health (angina)
Defaecation is painful (e.g. Haemorrhoids)
To clear the bowel before a procedure
To treat drug induced, bedridden, age-related constipation

Question 24

Which laxatives are faster acting, bulk or osmotic?

Answer 24

Osmotic

Question 25

Example of bulk laxative

Answer 25

Methylcellulose

Question 26

Example of osmotic laxative

Answer 26

``` Magnesium sulphate or hydroxide (orally) Sodium citrate (rectally) ```

Question 27

Examples of stimulant purgatives

Answer 27

Bisacodyl

Question 28

Example of faecal softener

Answer 28

``` Doc usage sodium (orally) Arachis oil (enema) ```

Question 29

What combination of drugs is used to control IBS?

Answer 29

Adjustment of diet Anti-diarrhoeals Laxatives

Question 30

What drugs are used for acute attacks of IBD?

Answer 30

Glucocorticoids

Question 31

What drugs are used in treatment of mild UC?

Answer 31

Aminosalycylates

Question 32

Examples of aminosalycylates?

Answer 32

Methalazkne Sulfazalazine Olsalazine

Question 33

What types of drugs have anti-motility effects?

Answer 33

Opiates

Question 34

What is the mechanism action of opiates in the GI tract?

Answer 34

``` Inhibit enteric neurones Decreased perostalsis Increased segmentation Increased fluid absorption Constriction of pyloric, ileocaecal and anal sphincters Increased tone of large intestine ```

Question 35

What are the major opiates that are used in diarrhoea?

Answer 35

Codeine Diphenoxylate Loperamide

Question 36

Mechanism of action of 5-ASA

Answer 36

Topical effect Anti-inflammatory properties Reduces risk of colon cancer

Question 37

Side effects of 5-ASAs

Answer 37

Diarrhoea | Idiosyncratic nephritis

Question 38

Side effects of steroids

Answer 38

``` A vascular necrosis Osteoporosis Acne Thinning of skin weight gain Diabetes Hypertension Cataracts Growth failure ```

Question 39

Examples of immunosuppressive agents used in UC and Crohn's

Answer 39

Adagio prime Mercaptopurine Methotreaxate

Question 40

Side effects of Azothioprine

Answer 40

Pancreatitis Leukopenia Hepatitis Small risk of lymphoma, skin cancer

Question 41

Example of anti-TNF therapy

Answer 41

Infliximab | Adalumimab

Question 42

What is it important to exclude before prescribing anti-TNF therapy?

Answer 42

Exclude current infection/ TB

Question 43

Is surgery for Crohn's curative?

Answer 43

No

Question 44

Is surgery for UC curative?

Answer 44

Yes can be

Question 45

What is the most common pathology of the biliary tract?

Answer 45

Cholelothiasis (gallstones)

Question 46

What is the usual treatment for gall stone?

Answer 46

Surgery

Question 47

What drug can be useful in the treatment of gallstones?

Answer 47

Ursodeoxycholic acid

Question 48

Pain relief used in the treatment of bi,airy tract disease

Answer 48

Morphine but constricts sphincter of oddi | Buprenorphine & pethidine are alternatives

Question 49

What drugs are used to relieve biliary spasm?

Answer 49

Atropine | GTN

Question 50

What is the main organ of drug metabolism?

Answer 50

Liver

Question 51

What is the first phase of drug metabolism?

Answer 51

Oxidation Reduction Hydrolysis

Question 52

What is phase 2 of drug metabolism?

Answer 52

Conjugation

Question 53

What mediates the oxidation reaction of the drug metabolism?

Answer 53

Haem proteins