Drug control in asthma Flashcards Preview

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Flashcards in Drug control in asthma Deck (51):
1

What is asthma?

Recurrent reversible obstruction of airflow in airways in response to non-noxious stimuli
Difficulty in breathing; wheezing; cough

2

What are reasons in having asthma?

Genetically susceptibility
Trigger also required
Allergic in >30%
Post-viral (after infection)
Psychogenic (e.g. stress can be an asthma trigger)

3

How many people are being treated for asthma in Scotland?

390,00

4

How many deaths a day are caused by asthma in the UK?

5 deaths/day (2000/yr)

5

What is extrinsic asthma?

Atopic, allergic

6

What is intrinsic asthma?

Non-atopic, non-allergic

7

What are triggers of asthma?

Pollen
Dust
Animal hair
Sting
Aspirin
Cold air
Irritant chemicals
Pollutants

8

What is the immune system?

Guards against bacteria, viruses, cancer and parasites. Normally a protective mechanisms

9

What is an antigen?

Protein or modified protein

10

How is antibody synthesis induced?

By monocytes (blood) macrophages, lymphocytes, mast cells- IgE

11

What is the equation for the immune reaction?

A/g + A/b --> immune reaction

12

What does cell-fixed a/b provide?

Recognition
Anchor
Trigger

13

What chemical mediators (cytokines) are released by the cell?

Interleukins
Prostaglandins (PG) --> recruit other cells to the site of infection
Leukotrienes (LT)
Thromboxanes (Tx)
Histamine
Platelet activating factor )PAF)

14

What are the effects of cytokine mediators?

Vasodilation
Pain/itch
Oedema- fluid leaks out of tissue, causes congestion
Smooth muscle contraction- contraction of bronchioles

15

What is an allergy?

An inappropriate immune response
Form of reaction, mediators involved, vary in different tissues

16

What are some effects of an allergic reaction?

Skin- rash, itch
Gut- vomitting
Eyes, nose- hypersecretion

17

What are the stages of asthma?

Intermediate
Late

18

What is the intermediate stage of asthma?

Bronchoconstriction (airways constrict), may or may not be vasodilation
Anaphylaxis leads to death

19

What are the late stages of asthma?

Oedema--> congestion
Hyper secretion --> mucus
Inflammatory cells
Bronchoconstriction and hyperreactivity

20

What does is mean if there is an increase in FEV1 in lungs?

Treatment is working, lungs are getting better

21

What is innervation of the lungs?

Parasympathetic
Sympathetic
Non-adrenergic non-cholinergic (NANC)
Sensory- irritation--> reflex constriction via parasympathetic

22

What are upper airways constricted by?

Ach via M3 receptors

23

What are M3 receptors?

Parasympathetic nerves

24

What constricts the lower airways?

NANC transmitters

25

What relaxes the lower airways?

NANC transmitters (e.g. NO) and circulating adrenaline (beta 2)

26

What is not in the airway muscle?

Sympathetic nerve supply

27

What constricts blood vessel smooth muscle?

NA from sympathetic nerves (alpha 1)

28

What relaxes blood vessel smooth muscle?

Circulating adrenaline (beta 2)

29

What system does mucus secretion decrease?

Sympathetic system

30

What system does mucus secretion increase?

Parasymathetic system, inflammatory mediators and chemical/physical stimuli

31

What is the immediate phase of drug therapy?

Smooth muscle relaxants (treat bronchospasm)

32

What is the late phase of drug therapy?

Steroids (treat inflammation)

33

What drugs are used to treat asthma?

Beta-adrenoreceptors agonists
Muscarinic antagonists
Theophylline
Antihistamines
LT antagonists
Glucocorticoids (anti-inflammatory steroids)

34

What are beta-adrenoceptor agonists?

Adrenaline
Alpha + beta agonist

35

What do B1 adrenoreceptors agonists affect?

Heart

36

What do B2 adrenoreceptor agonists affect?

Bronchi

37

What is salbutamol?

Beta 2 only
Inhaled aerosol or powder

38

What does saltbutamol do?

Relaxes bronchioles
Decreases secretion
Increases FEV1

39

What is the mechanism of saltbutamol?

Increases adenylate cyclase
Increases cAMP
Decreases Ca2+ entry

40

What are examples of drugs for muscarinic antagonists?

Ipratropium
Tiotropium

41

What does Ipratropium do?

N+ poor absorber
Blocks bronchoconstriction due to parasympathetic reflex
More useful in bronchitis

42

What does Tiotropium do?

Prolonged (24hr) M3 selective muscarinic antagonist
Better than the older ipratropium

43

What is theophylline?

Bronchodilator

44

How does theophylline relax smooth muscle?

Inhibition of phosphodiesterase
Increases cAMP
Increases cGMP
Increases release of NA and Adr

45

What are some possible serious side effects of theophylline?

Arrythmia, convulsions, low TI

46

What benefits are antihistamines?

Little benefit in asthma (much more in hayfever etc)

47

What do antagonists of leukotrienes (LTs) do?

Drugs to block either the LT receptor or the synthesis of LTs
E.g. montelukast

48

What is an example of a useful glucocorticoid (anti-inflammatory steroids)?

Beclomethasone- very important as prohphylactic

49

How do glucocorticoides suppress immune system?

Decreases lymphocyte and mass cell number
Decreases reactivity
Decreases mediator synthesis and release
Decreases b.v. permeability

50

What is the glucocorticoid mechanism?

Cytoplasmic receptor
Nuclear binding
RNA fro lipocortin (Annexin-1)
Block PLA2
Block COX-2

51

What are the advantages of inhalation?

Rapid response
Targetted at bronchi
Need less drug
Less side effects
Avoid liver metabolism