Clinical Pharmacology of the Alimentary System Flashcards Preview

Alimentary System > Clinical Pharmacology of the Alimentary System > Flashcards

Flashcards in Clinical Pharmacology of the Alimentary System Deck (65):
1

What is the most common symptom of malignancy in terms of altered bowel habit?

Diarrhoea

2

What are the main drug classes used in treatment of alimentary disease?

Acid suppressing
Drugs affecting GI motility
Laxatives
Drugs for IBD
Drugs affecting intestinal secretions

3

Give an example of a drug used for acid suppression in alimentary disease

Antacids
H2 receptor antagonists
Proton pump inhibitors

4

give an example of a drug used to affect GI motility in alimentary disease

Anti-emetics
Anti-muscarinics/anti-spasmodics
Anti-motility drugs

5

Give an example of a drug type used for IBD

Aminosalicylates
Corticosteroids
Immunosuppressants
Biologics

6

What do antacids contain that neutralises gastric acid?

Magnesium or aluminium

7

How do alginates help acid reflux?

They form a viscous gel which floats on the stomach contents and reduces reflux

8

What do H2 receptor antagonists block?

Histamine receptors

9

In what diseases are H2 receptor antagonists indicated?

GORD
Peptic ulcer disease

10

How can H2 receptor antagonists be administered?

Orally or intravenously

11

In what diseases are proton pump inhibitors indicated?

GORD
Peptic ulcer disease

12

How can proton pump inhibitors be administered?

Orally or intravenously

13

When would triple therapy including a proton pump inhibitor be indicated?

For treatment of peptic or duodenal ulcers associated with H. pylori

14

Proton pump inhibitors can cause a predisposition to what?

Clostridium difficile infection
Hypomagenesaemia
B12 deficiency

15

What do prokinetic agents increase?

Gut motility and gastric emptying

16

When would prokinetic agents be indicated?

GORD
Gastroparesis
(constipation)

17

Give an example of a prokinetic agent

Anti-emetics
Laxatives
e.g Metoclopramide, Domperidone

18

Give an example of a drug which can be used to treat diarrhoea i.e. which decrease motility

Loperamide
Opiates

19

What is the mechanism of action of drugs which decrease gut motility?

Via opiate receptors in the GI tract to decrease ACh release and smooth muscle contraction and increase anal sphincter tone

20

What are the mechanisms of action of anti-spasmodics?

Anti-cholinergic muscarinic antagonists
Direct smooth muscle relaxants
Calcium channel blockers

21

How do anti-cholinergic muscarinic antagonists work?

Inhibit smooth muscle contraction in the gut wall, producing muscle relaxation and reducing spasm

22

Give the different types of laxative and an example of each

Bulk - Isphagula
Osmotic - Lactulose
Stimulant - Senna
Softeners - Arachis oil

23

How do laxatives work?

By increasing the bulk of fluid drawn into the gut

24

What cause of constipation do you need to rule out before prescribing laxatives?

Obstruction - giving laxatives when constipation is due to obstruction could cause rupture, megacolon etc.

25

Give an example of an aminosalicylate

Mesalazine
Olzalazine
Sulfasalazine

26

Aminosalicylates are first line treatment in

inflammatory bowel disease

27

Where are aminosalicylates metabolised?

In the liver

28

When should aminosalicylates be avoided?

If the patient is allergic to salicylates

29

How can corticosteroids be administered?

Orally
Intravenously
Rectally

30

Give an adverse effect of corticosteroids

Diabetes
Osteoporosis
Hypertension
Cushing's disease
Increased risk of infection

31

If a patient on corticosteroids becomes acutely unwell, should you withdraw or increase their corticosteroid dose?

Increase (double)

32

How do immunosuppressants work?

Prevent formation of purines which are required for DNA synthesis, so reduces immune cell proliferation

33

Adverse effects of immunosuppressants mainly relate to

bone marrow suppression

34

How to biologics work?

Prevent action of TNF-alpha which is a key cytokine in inflammatory response

35

What are the contra-indications for immunosuppressant use?

Current TB, or other serious infection
Multiple sclerosis
Pregnancy or breast feeding

36

Give an adverse effect of immunosuppressants

Increased risk of infection, particularly TB
Infusion reaction causing fever and itch
Anaemia
Thrombocytopenia
Neutropenia
Malignancy

37

Give an example of a drug affecting biliary secretion

Cholestyramine
Ursodeoxycholic acid

38

How does cholestyramine work?

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

39

Other than bile salts, what might cholestyramine affect?

Absorption of other drugs (should be taken separately)
Fat soluble vitamin absorption

40

Ursodeoxycholic acid is used to treat

gallstones and primary biliary cirrhosis

41

Gastrointestinal or liver disease can affect the processes of drug;

Absorption
Distribution
Metabolism
Excretion

42

Drug absorption is affected by

pH
gut length
transit time

43

The rate of drug absorption in GI/liver disease is more affected than

the total drug absorption

44

Drug distribution can be affected by

low albumin levels

45

Drug metabolism is affected by;

liver enzyme concentration
gut wall metabolism

46

What percentage of adverse drug reactions does GI upset account for?

20-40%

47

What drugs are commonly responsible for diarrhoea/constipation?

Cholinergics
NSAIDs
Antimicrobials
Opiates
Anticholinergics
Opiates

48

Give an example of a mechanism affected by drugs causing diarrhoea/constipation

Osmotic
Secretory
Transit time
Protein absorption

49

25% of drug induced diarrhoea is due to

antimicrobials

50

GI bleeding/ulceration accounts for what percentage of hospital admissions due to adverse drug reactions?

6.5%

51

What drugs, taken by a high percentage of the elderly population, are common causes of GI bleeding/ulceration?

Low dose aspirin
NSAIDs
Warfarin

52

Changes to gut bacteria is mainly due to

antibiotics

53

Give an adverse effect of changes in gut bacteria due to antibiotics

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

54

What are the features of intrinsic hepatotoxicity (type A ADR)?

Predictable
Dose dependent
Acute
e.g. paracetamol overdose

55

What are the features of idiosyncratic hepatotoxicity (type B ADR)?

Unpredictable
Not dose dependent
Can occur at any time
May be part of a hypersensitivity reaction
Can be due to the drug itself or an active metabolite

56

What are the most common types of drug induced liver injury?

Hepatitis
Cholestasis

57

What are the risk factors for drug induced liver injury?

Age
Female
Alcohol consumption
Genetic
Malnourishment

58

When prescribing for a patient with liver disease, what needs to be considered?

Risk factors of drug induced liver injury
Severity of liver disease

59

What classification can be used to assess the severity of liver disease in a patient?

Child-Pugh classification

60

The Child-Pugh score separates liver disease into what three classifications, and which has the worst prognosis?

A - score < 7
B - score 7-9
C - score > 9

C has the worst prognosis

61

In prescribing for a patient with liver disease, care should be taken to avoid drugs which;

Can be toxic due to changes in pharmacokinetics
Are hepatotoxic
May worsen non-liver aspects of disease e.g. ascites

62

Drugs prescribed to patients with liver disease should have what kind of therapeutic index?

Wide therapeutic index

63

Give an example of a drug which should be avoided in patients with liver disease

Methotrexate
Azathioprine
Bensodiazepines

64

Caution should be taken when prescribing what kind of drugs to patients with liver disease?

Warfarin/anticoagulants
Aspirin
NSAIDs
Opiates
Benzodiazepines

65

When can you find information about risks with specific drugs in liver disease?

British National Formulary (BNF)