Pharmacology

Question 1

What are the types of GI drug?

Answer 1

Acid suppressants
Drugs affecting motility
Laxatives
IBD drugs
Drugs affecting intestinal secretions

Question 2

What are the types of acid suppressants?

Answer 2

Antacids
H2 receptor antagonists
Proton pump inhibitors

Question 3

What drugs affect GI motility?

Answer 3

Anti-emetics
Antimuscarinics/other antispasmodics
Antimotility

Question 4

What are the types of IBD drug?

Answer 4

Aminosalicylates
Corticosteroids
Immunosuppressants
Biologics

Question 5

What are the types of drug affecting intestinal secretions?

Answer 5

Bile acid sequestrates

Urodeocycolic acid

Question 6

How do antacids work?

Answer 6

Neutralise gastric acid

Question 7

What are alginates?

Answer 7

A type of antacid that works by forming a viscous gel that floats on stomach contents and reduces reflux

Question 8

How do H2 receptor antagonists work?

Answer 8

Block histamine receptor, and thereby reducing acid secretion

Question 9

When are H2indicated for use?

Answer 9

GORD

Peptic ulcer disease

Question 10

How are H2 receptor antagonists given?

Answer 10

Oral or IV

Question 11

How do proton pump inhibitors work?

Answer 11

Block proton pump and thereby reduce acid secretion

Question 12

When are proton pump inhibitors indicated for use?

Answer 12

GORD
Peptic ulcer disease
Triple therapy for treatment of PU/DU associated H pylori

Question 13

What are the problems associated with proton pump inhibitor use?

Answer 13

GI upset

Predisposition to c. diff, hypomagnesaemia, B12 deficiency

Question 14

What do pro kinetic agents do?

Answer 14

Increase gut motility and gastric emptying

Question 15

What are pro kinetic agents used for?

Answer 15

Gastroparesis
GORD
as antiemetics

Question 16

How do prokinetics work?

Answer 16

Unclear

Involves parasympathetic nervous system control of smooth muscle and sphincter tone

Question 17

What can drugs which decrease motility be used for?

Answer 17

Clinical benefit i.e. antidiarrhoea

Cause unwanted effects i.e. constipation

Question 18

How do drugs decreasing motility work?

Answer 18

Via opiate receptors in GI tract to decrease Ach release, decreasing smooth muscle contraction and increasing anal sphincter tone

Question 19

What are antispasmodics used for?

Answer 19

IBS

Renal colic

Question 20

What are the 3 mechanisms of antispasmodics action?

Answer 20

Anti cholinergic muscarinic antagonists
Direct smooth muscle relaxants
CCBs reducing Ca required for smooth muscle contraction

Question 21

What are the 4 types of laxatives?

Answer 21

Bulk
Osmotic
Stimulant
Softeners

Question 22

What are the issues associated with laxatives?

Answer 22

Obstruction
Route of adminisation
Need for other measures
Misuse

Question 23

Wat is the mechanism of action of aminosalicylates?

Answer 23

Unclear but anti inflammatory

Question 24

What are the adverse effects of aminosalicylates?

Answer 24

GI upset
Blood dycrasias
Renal impairment

Question 25

How do corticosteroids work?

Answer 25

Antiinflmmatory

Question 26

What are the complications of corticosteroids?

Answer 26

Increases susceptibility to infection | Addisonian crisis with abrupt withdrawal

Question 27

How do immunosuppressants work?

Answer 27

Prevents formation of purines required for DNA system thesis so reduces immune cell proliferation

Question 28

What are the adverse effects of immunosuppressants?

Answer 28

Mainly relate to bone marrow suppression Asatioprine hypersensitivity Organ damage

Question 29

How do biologics work?

Answer 29

Addresses inflammatory response but not underlying disease process

Question 30

What are the contraindications for biologics use

Answer 30

Current TB or other serious infection MS Pregnancy/breastfeeding

Question 31

What are the adverse effects of biologics?

Answer 31

``` Risk of infection, esp TB Infusion reaction Anaemia, thrombocytopenia, neutropenia Demyelination Malignancy ```

Question 32

How does cholestryamine work?

Answer 32

Reduces bile salts by binding with them in the gut and then excreting them as an insoluble complex

Question 33

What is ursodeoxycholic acid used to treat>

Answer 33

Gallstones and primary biliary cirrhosis

Question 34

How does ursodeoxycholic acid work?

Answer 34

Inhibits an enzyme involved in the formation of cholesterol, altering the amount of bile and slowly dissolving non calcified stones

Question 35

What can affect the ADME processes of a drug?

Answer 35

Gi or liver disease

Question 36

What can affect the absorption of a drug?

Answer 36

pH Gut length Transit time

Question 37

What can affect the distribution of a drug and how?

Answer 37

Low albumin- decreased binding and increased free drug concentration

Question 38

What can affect the metabolism of a drug?

Answer 38

Liver enzymes Gut bacteria Gut wall metabolism Liver blood flow

Question 39

What are the most common GI adverse effects?

Answer 39

``` GI upset COnstipation/diarrhoea GI bleeding/ulceration Changes to gut bacteria Liver injury ```

Question 40

What causes changes to gut bacteria?

Answer 40

Mainly antibiotics

Question 41

What can changes in gut bacteria cause?

Answer 41

Loss of OCP activity Reduced vit K absorption Overgrowth of pathogenic bacteria

Question 42

What are the 2 types of drug induced liver injury?

Answer 42

Intrinsic hepatotoxicity | Idiosyncratic hepatotoxicity

Question 43

What is intrinsic hepatotoxicity?

Answer 43

Predictable, dose dependent, acute reaction

Question 44

What is idiosyncratic hepatotoxicity?

Answer 44

Unpredictable, not dose dependent, may occur at amy time and be part of hypersensitivity reaction

Question 45

What are the risk factors for drug induced liver injury?

Answer 45

``` Age Female Alcohol consumption Genetic factors Malnourishment ```

Question 46

How is the severity of liver disease classified?

Answer 46

Child-Pugh classification

Question 47

What does the Child-Pugh classification look at?

Answer 47

``` Bilirubin Albumin PT Encephalopathy Ascites ```

Question 48

What are the 2 year survival rates in the Child-Pugh classification system?

Answer 48

``` <7= 85% 7-9= 57% >9= 35% ```

Question 49

When should care be taken when prescribing in patients with liver disease?

Answer 49

Drugs which can be toxic due to changes in pharmacokinetics Drugs with hepatotoxicity or may worsen non liver aspects of liver disease Warfarin/anticoagulents Aspirin/NSAIDs Opiates/benzodiazepines

Question 50

Why must care be taken in liver disease with warfarin/anticoagulents?

Answer 50

Clotting factors already low

Question 51

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

Answer 51

Increase bleeding time | Worsen ascites

Question 52

Why must care be taken in liver disease with opiates/benzodiazepines?

Answer 52

May precipitate encephalopathy by increasing sedation