Alimentary Pharmacology

Question 1

What are the main roles of drugs used for alimentary disease?

Answer 1

Acid suppression
GI motility
Laxatives
IBD
Intestinal secretion

Question 2

How do H2 antagonists block acid production?

Answer 2

Blocking the H2 histamine receptor which stimulates proton pump activity

Question 3

How do PPIs block acid production?

Answer 3

Directly blocking the activity of proton pumps

Question 4

How do alginates work?

Answer 4

Form a viscous gel which floats on stomach contents and reduces reflux

Question 5

How do antacids work?

Answer 5

Contain Mg or Al, neutralising stomach acid

Question 6

When are H2 antagonists indicated?

Answer 6

GORD, Peptic ulcer

Question 7

When are PPIs indicated?

Answer 7

GORD, Peptic ulcer

H. pylori (triple therapy)

Question 8

PPIs are associated with what side effects?

Answer 8

Hypomagnesaemia
B12 Deficiency
? C. diff infection

Question 9

What is the function of prokinetic agents?

Answer 9

Increased gut motility, gastric emptying

Question 10

Give an example of H2 antagonists?

Answer 10

Ranitidine

Question 11

Which drugs directly inhibit the vomiting centre of the medulla?

Answer 11

Anti-muscarinics

Anti-histamines

Question 12

Which drugs inhibit vomiting via the Chemoreceptor trigger zone?

Answer 12

Dopamine antagonists
5HT3 antagonists
Cannabinoids

Question 13

Which drugs decrease gastric motility?

Answer 13

Loperamide

Opioids

Question 14

By what mechanism do anti-diarrhoea drugs have their effect?

Answer 14

Opioid receptors in GIT, decrease ACh release

Question 15

Why does Loperamide have few central opioid effects?

Answer 15

Not well absorbed across the blood-brain barrier

Question 16

What are anti-spasmodics?

Answer 16

Reduction of symptoms of IBS and renal colic

Question 17

What are the mechanisms of anti-spasmodic drugs?

Answer 17

Muscarinic antagonists
Direct smooth muscle relaxants
CCBs

Question 18

What are the 4 types of laxative?

Answer 18

Bulk
Osmotic
Stimulant
Softener

Question 19

What are the main drugs used in IBD?

Answer 19

Aminosalicylates
Corticosteroids
Immunosuppressants
Biologics

Question 20

How are aminosalicylates administered? When are they contraindicated?

Answer 20

Oral/rectal
Renal impairment
Allergy

Question 21

What are the adverse effects associated with use of aminosalicylates?

Answer 21

GI upset
Renal impairment
Acute pancreatitis

Question 22

What is associated with abrupt withdrawal of corticosteroids?

Answer 22

Addisonian Crisis

acute cortisol insufficiency

Question 23

What are the contraindications/concerns with corticosteroids?

Answer 23

Osteoporosis
Cushingoid features
Infection susceptibility

Question 24

How do immunosuppressants work to reduce the symptoms of IBD?

Answer 24

Prevent purine formation required for DNA synthesis - reduced immune cell proliferation

Question 25

What are the adverse effects of immunosuppressants?

Answer 25

Azathioprine hypersensitivity Bone marrow suppression Organ damage

Question 26

How do biologics work in treatment of IBD?

Answer 26

Anti- TNFa (proinflammatory cytokine) | Only treat inflammatory response

Question 27

What biologic is commonly used in IBD?

Answer 27

Infliximab

Question 28

When is Infliximab contraindicated?

Answer 28

Current TB, serious infection MS Pregnancy/breast feeding

Question 29

What are the adverse effects of Infliximab?

Answer 29

Increased infection risk Infusion reaction Anaemia Malignancy

Question 30

When do biologics increase the risk of malignancy

Answer 30

Crohn's disease

Question 31

Which drugs affect biliary secretion?

Answer 31

Cholestyramine | Ursodeoxycholic Acid

Question 32

For what is Cholestyramine indicated?

Answer 32

Patients presenting with pruritis due to biliary cause

Question 33

What is the mechanism of Cholestyramine?

Answer 33

Reduced bile salts, binds them in gut and excretes as insoluble complex

Question 34

What is a risk associated with use of Cholestyramine?

Answer 34

May effect the absorption of other drugs and fat soluble vitamins (inc. Vit K)

Question 35

When is Ursodeoxycholic acid indicated?

Answer 35

Gallstones | Primary Biliary Cirrhosis

Question 36

How does Ursodeoxycholic acid work?

Answer 36

Inhibits enzyme in formation of cholesterol, slowly dissolving NON-CALCIFIED stones

Question 37

How may GI issues cause changes in drug distribution?

Answer 37

Low albumin causes a decrease in the amount of bound drug (more free drug)

Question 38

How may GI issues cause changes in drug absorption?

Answer 38

Changes: pH Gut length Transit time

Question 39

How may GI issues cause changes in drug metabolism?

Answer 39

Liver enzymes, blood flow Increased gut flora Gut wall metabolism

Question 40

How may GI issues cause changes in drug excretion?

Answer 40

Biliary excretion impairment (can increase toxicity)

Question 41

What is the largest cause of drug-induced diarrhoea?

Answer 41

Antimicrobials

Question 42

What are the most common GI adverse effects of medication?

Answer 42

GI upset GI bleed/ulceration Changes to gut flora Induced Liver injury

Question 43

What are the risk factors for GI adverse drug effects?

Answer 43

``` Female Elderly Alcoholics Malnourishment ?Genetics ```

Question 44

Changes to gut bacteria due to adverse drug effects may cause what?

Answer 44

Reduced Vit K absorption (increased INR) | Overgrowth of pathogenic bacteria (C. diff)

Question 45

What is the difference between type A and B drug induced liver injury (hepatotoxicity)?

Answer 45

A: Intrinsic - predictable, dose-dependent, acute B: Idiosyncratic - unpredictable

Question 46

Idiosyncratic hepatotoxicity mostly presents as what?

Answer 46

Hepatitis | Cholestasis

Question 47

How is liver disease classified?

Answer 47

Child-Pugh classification

Question 48

What must be taken into consideration when prescribing to a patient with liver disease?

Answer 48

Hepatotoxic drugs Encephalopathic drugs Drugs which change pharmacokinetics

Question 49

Why must care be taken when prescribing warfarin in liver disease?

Answer 49

Clotting factors will likely already be low

Question 50

Why must care be taken when prescribing aspirin/NSAIDs in liver disease?

Answer 50

Can increase bleeding time | NSAIDs can worsen ascites

Question 51

Why must care be taken when prescribing Opiates/benzos in liver disease?

Answer 51

May precipitate encephalopathy

Question 52

In a patient with Liver disease, which drugs should particular care be taken in prescribing?

Answer 52

Warfarin/Anti-coags NSAIDs Opiates/benzos