Lecture 12 - Respiratory Pharmacology Flashcards Preview

Respiratory physiology > Lecture 12 - Respiratory Pharmacology > Flashcards

Flashcards in Lecture 12 - Respiratory Pharmacology Deck (62):
1

What is a cough

symotom of a respiratory disease
Protective reflect: prevents lungs from aspiration

2

What is a useless cough

persistent and unproductive: dry
eg. ashtma, oesophageal reflux, sinusitis and psychogenic

3

Should a useless cough be suprressed?

yes it should
cough supressants are called - antitussives
always treat underlying cause as cough is a symptom

4

What is a useful cough?

expels secretions i.e sputum - productive
eg. chest infection

5

Should a useful cough be suppressed?

No
yes if it is exhausting and dangerous

6

Mechanism of a cough

Cough receptors in nose or upper airways (lung irritant receptors detected. goes to the
cough centre in the medulla which leads to stimulation leading to cough

7

How do dry cough - cough suprressants act? and what drugs act to reduce that afferent side

On the afferent side: reduce stimuli
- above larynx - linctuses
Below larynx - steam inhalation, nebulised local anaesthetics
Treat cause: stop smoking

8

What happens on the efferent side: in dry cough suppressants?

Medullary cough centre - antitussives
- opiods (codeine, methadone, pholcodeine)
- non opiods (dextromethorphan, noscapine)
- sedatives: diphenhydramine, chlorpheniramine

9

Efferemt side antitussives

Opiods (codeine, methadone, pholcodeine)
Non opiods (dextromethorphan, noscapine)
Sedatives: diphenhydramine, chlorpheniramine

10

Productive cough

Expectorants which increase volume of secretion and mucolytics which decrease the viscosity

11

Examples of expectorants

Guaiphenesin, ipecacuanha

12

Examples of mucolytics

Acetyl cysteine, recombinaant humane DNase
used for cystic fibrosis

13

What is the best treatment for a productive cough that shouldn't be suppressed?

antibiotics

14

3 common causes of a chronic caugh

upper airways cough syndrome - post nasal drip
bronchial asthma/COPD
Gastrooesophageal reflux disease

15

Treatment for upper airways cough syndrome - post nasal drip?

anti- allergics, and nasal decongestants

16

Gastroesophageal reflux disease

anti-reflux therapy with PPi's

17

What are the causes of chronic obstructive lung diseases

inflammation, bronchoconstriction and secretions (mucus plugs)

18

What are the types of bronchial asthma

associated with allergic reactions - Type 1 hypersensitivity
not associated with specific allergen
exercise induced asthma
asthma associated with COPD

19

Describe the pathology of allergen mediated asthma

Antigen is presented through TH 2 cell to a B cell which induces IgE production and Mast cell activation. This mediates the release of mediators (histamine) and causes the pharmacological effects - bronchoconstriction

20

Treatment of asthma

non-specific reduction of bronchial hypersensitity -
non - pharmacological : stop smoking, weight reduction
pharmacological: corticosteroids
Dilation of narrowed bronchi
mimicking dilators: sympathomimetics
direct acting bronchodilators: methylaxines
Blockade of constrictor transmitter: Anti-cholinergics
Prevention of release of transmitter
- mast cell stabilisers
Antagonism of released transmitter
- leukotriene receptor antagonists

21

How to prevent an antigen:antibody reaction

avoidance of allergen
-difficult to find
-insufficient evidence
-avoidance of tobacco and weight reduction

22

What do corticosteroids do

anti-inflammatory - inhibit influx of inflamm cells, reduce microvascular leakage - decreased oedema
reduce bronchial reactivity - reduce asthma exacerbations and do not relax bronchial smooth muscle

23

What are the different types of corticosteroids?

inhaled and oral

24

Inhaled corticosteroids - first line for asthma

beclomethasone, budesonide
fluticasone, flunisolide, triamcinolone
first line regular therapy - mild to mod asthma

25

oral corticosteroids - for sever asthma

Prednisolone, methylprednisolone
Betamethasone and triamcinolone
for severe asthma

26

What are the adverse effects of corticosteroids

Iatrogenic Cushings syndrome
- diabetes, hypertension, peptic ulcer, psychosis, delayed puberty
Inhibition of hypothalamic pituitary axis
Other side effects
-oropharyngeal candidiasis
-hoarseness: direct effect vocal cords

27

Which corticosteroid produces less side effects

cyclesonide - prodrug

28

How do mast cell stabilisers work and examples?

cromolyn sodium, nedocromil sodium
- inhibit release of mediators - histamine

29

How are mast cell stabilisers administered

by inhalation and very poorly absorbed
no effect on bronchial smooth muscle
no use in acute bronchospasms

30

When are mast cell stabilisers useful

when taken prophylactically (as a preventative defensive measure)
main uses: allergy rhinitis, allergic conjunctivitis
side effects: throat irritation, cough, dermatitis, myositis and gastroenteritis

31

What do Leukotriene pathway inhibitors do?

prevents bronchospasms.
arachidonic acid produces leukotrienes and prostaglandins. 5 They inhibit Lipoxygenase which cause leukotriene synthesis and leukotriene receptor antagonists block receptors from causing bronchospasms.

32

Inhibition of leukotriene synthesis occurs by

inhibition of 5-lipoxygenase
zileuton - discontinued liver toxicity

33

Inhibition of leukotriene receptors done by

inhibit binding of leukotriene to receptor

34

leukotriene receptor inhibitors

montelukast, zafirlukast

35

When are leukotriene receptor antagonists used?

allergen induced asthma, exercise induced asthma
reduce frequency of exacerbations
given orally: good for children.

36

Are leukotriene receptor anatagonists useful in acute asthma

nope

37

side effects of leukotriene receptor anatagonists

headache, gastritis, flu-like symptoms

38

commonly used leukotriene receptor anatagonists

montelukast - receptor blocker

39

How is bronchial tone controlled

Theophylline and muscarinic antagonists cause bronchodilation.
bronchial dilator drugs
sympathomimetics
parasymptholytic agents
- anticholinergic drugs
Methylxanthines

40

Sympathomimetic

- Act via B2 adrenoceptors
selective B2 agonist agents
-short acting
albuterol, salbutamol - most common terbutaline, fenoterol, metaproterenol
Long acting - salmetrol, formetrol
Non-selective - adrenaline - use in emergency as subcutaneous injection

41

Selective B2 agonists

dose inhalers or nebulisation
onset - immediate
peak 15-30 mins
duration 3-4 hours
first line therapy
albuterol-salbutamol

42

Side effects of selective B 2 agonists

due to b2 receptors in heart muscle and other tissues
- palpitations, tachycardia, cardiac arrhythmias tremor, restlessness, nervousness, hypokalaemia

43

What role do Phosphodiesterase inhibitors play in bronchodilation

decrease in breakdown of cAMP and hence cause dilation

44

Methylxanthines

oral or IV
adjuvant therapy in asthma

45

Adverse effects of methylxanthines

palpitations, cardiac arrhythmia, hypotension
GI irritation
diuresis, hypokalaemia
anxiety, headache, seizures
therapeutic window - 55-110 mmol/l

46

Theophylline

methylxanthine
oral: rapid and complete absorption
90% metabolised
adjuvant therapy

47

Aminophylline is used for?
and how is it administered?

intravenous
sever asthma

48

What do anti-cholinergic agents do

act via inhibiting musarinic receptors
selective type: ipratropium, tiotropium, oxitropium
inhibits effects of vagus nerve stimulation

49

How are anti-cholinergics administered and what are the adverse effects?

inhalation
adjuvant therapy in acute sever asthma, COPD
Adverse effects:
- airway irritation
-anticholinergic effects
-GI upset, urinary retention

50

long acting anti-cholinergics

tiotropium

51

anti cholinergic - colour

green inhalers

52

corticosteroids - colour

brown inhalers

53

Selective short acting B2 agonists colour

blue inhalers

54

Anti IgE monoclonal antibody

Omalizumab
inhibits binding of IgE to mast cells
Repeat administration
- lessens asthma severity
-reduces magnitude of response
-reduced requirement of steroids
-very expensive

55

Anti IgE monoclonal antibody example

Omalizumab

56

Ketotifen

Histamine receptor antagonist
some anti-asthma effect
side effects: drowsiness
no proven benefit

57

Magnesium

patients who fail to respond to inhaled bronchodilators
IV infusion

58

Ketamine/ volatile anaesthetic agents

anaesthetic agents
bronchodilator properties
no role in routine management
used in life threatening or near fatal asthma

59

is asthma reversible?

yes it is

60

COPD reversibility

incompletely reversible airway obstruction

61

COPD characteristics

occurs in older patients
progressive worsening over age

62

COPD treatment

approach same as for asthma
Anti-muscarinics - more effective than b2 agonists in COPD
Smoking cessation - major role in COPD