Respiratory Pharmacology

Question 1

How much of an inhaled bronchodilator reaches the lungs

Answer 1

10%

Question 2

What intracellular mediators result in broncodilation and constriction

Answer 2

Dilation cAMP
constriction cGMP

Question 3

How are leukotriens produced
Which ones are spasmodic

Answer 3

5-lipoxygenase binds to cell membrane forming a complex with 5LP activating protein. This changes arachadronic acid into leukotrien A4 - this is then used to create any of a whole family of leukotrines of which LTC4, D4 and E4 are spasmogenic

Question 4

Excretion of salbutamol

Answer 4

Conjugated in liver
Excreted in urine both conjugated and unchanged

Question 5

Advantages of terbutaline over salbutamol
Other use

Answer 5

Less sympathomimetic side effects
Stimulates surfactant production in neonates
Uterine relaxants in premature labour (all beta 2 agonists)

Question 6

Dose of nebulised adrenaline for croup or laryngeal oedema

Answer 6

0.5ml/kg of 1:1000 up to max of 5ml!

Question 7

Effects of inhaled anticholinergic on lungs

Answer 7

Bronchodilatation
Reduced airway resistance
Increased anatomical dead space
Increased physiological dead space

Question 8

Peak of ipratropium effect and duration
Excretion

Answer 8

2 hrs to peak
4-6 hr duration
Drug into oral tract 70% unchanged into faeces, systemically absorbed metabolism by liver

Question 9

Aadvantage of tiotropium over ipratropium

Answer 9

Longer half life so can be given just once a day
Perferentially binds to M1 (causing broncodilation) and not M2 (which triggers further ach release) like ipratropium does

Question 10

Examples of methylxanthines

Answer 10

Caffine, theophylline

Question 11

Effects of meythlxanthines

Answer 11

Central stimulant effect
Phosphodiesterase inhibition
Facilitates beta 2 action
Enhanced ca release
Adenosine receptor antagonist

Question 12

Clinical effect of meythlxanthenes

Answer 12

Bronchodilation and increased anatomical dead space
Increased respiratory work with less fatigue (increased rr and muscle work)
Increase in heart rate and cardiac contractility
Reduced pvr
Stimulate gastric acid
Stimulate diuresis
Inhibit uterine contraction

Question 13

Why is theophylline unpredictable orally

Answer 13

Variable protein binding
Rapid elimination by liver

Question 14

Difference between aminophylline and theophylline

Answer 14

Aminophylline is more water soluble so can be given iV

Question 15

Effects of inhaled steroids on resp system

Answer 15

Decreased mucus secretion and oedema
Decreased pvr
Reduced inflammation
Reduced vascular permiabitlih
Stabilisation of mast cells

Question 16

What is the use of sodium cromoglicate
Mechanism

Answer 16

Membrane stabilisation
Prevention of Bronchospasm only - not treatment
Inhibits platelet activation factor on esonophils, mast cells and platelets
Suppresses axonal simulation from irritants

Question 17

Bioavailability of cromoglicate
Protein binding
Excretion

Answer 17

1% orally, 10% inhaled
70% bound
Unchanged in urine and bile

Question 18

Effects of leukotrines on airways

Answer 18

Increase mucus production
Oedema
Eosinophil migration
Bronchoconstriction
Airway hyper responsiveness

Question 19

Effect of leukotrine receptor antagonist

Answer 19

Block LT1 receptor reducing bronchoconstriction
Block leukotrine production

Question 20

What sort of asthma is most effectively treated with leukotrine antagonists

Answer 20

Exercise induced and aspirin induced

Question 21

What is doxapram
Mechanism

Answer 21

Respiratory centre stimulant
Stimulates centrally and at carotid sinus chemoreceptors to increase tidal vol and resp rate

Question 22

Uses of doxapram
When not to use
Side effects

Answer 22

Useful in patients with central resp depression from resp disease or drug therapy
Not to use with resp obstruction as drive is still there
Side effects include other stimulation eg convulsions anxiety restlessness

Question 23

Examples of mucolytics

Answer 23

Carbocisteine, Dornase alpha

Question 24

Origin of surfactant treatment in neonates

Answer 24

Porcine, bovine or synthetic