pharmacology asthma

Question 1

Therapeutic objectives for a child with asthma?

Answer 1

Reduce wheeze, help symptoms, prevent another attack

Question 2

Why side effects for salbutamol?

Answer 2

Because salbutamol not good at selectively binding β-2 adrenergic receptor, so can bind β-1 adrenergic receptor in heart (conduction region) increasing calcium entry in heart and causing palpitations, tachycardias, arrhythmias.

Question 3

What is a nebuliser and its benefits?

Answer 3

Device that delivers high dose medicines quickly easily by changing liquid medicine into mist and breathing it in via facemask/mouthpiece. Advantages: minimal patient cooperation needed & can run them on oxygen simultaneously and doesn’t need technique

Question 4

What is a spacer and its benefits?

Answer 4

Device attached to inhaler making it easier/more effective. Less technique needed and lose a lot less of drug to the stomach.

Question 5

Why is inhaled route preferred from an oral route for salbutamol?

Answer 5

Inhaled dose is 10x smaller than oral dose so reduced side effects. If taken orally distributed around other systems. Less dose + less side effects

Question 6

For children under 5 what is the management of asthma?

Answer 6

SABA–> SABA+ ICS –> SABA + ICS + LTRA –> specialist

Question 7

How do NSAIDS worsen asthma? What drug is good for NSAID induced asthma?

Answer 7

Normally arachidonic acid converted to prostaglandins (with COX) or leukotrienes. NSAIDS inhibit COX so more leukotrienes produced. Leukotrienes cause bronchospasm and bronchoconstriction worsening asthma. Leukotriene receptor antagonists (eg. Montelukast)

Question 8

Salbutamol mechanism of action?

Answer 8

Agonist at β2 adrenergic receptor on airway smooth muscle cells, reducing calcium ion influx, preventing smooth muscle contraction.

Question 9

Salbutamol target?

Answer 9

Β2 adrenergic receptor on airway smooth muscle cells

Question 10

Salbutamol side effects?

Answer 10

Palpitations/agitations, tachycardia/arrhythmia, (due to effects on β-1 adrenergic receptor in heart) hypokalaemia at high doses

Question 11

Salbutamol type of drug + half life?

Answer 11

SABA (short acting beta agonist) half life 2.5-5h

Question 12

Where do salbutamol side effects happen? Why hypokalaemia?

Answer 12

Salbutamol cardiac side effects at β1 adrenergic receptor in heart. Hypokalaemia via effect on sodium potassium ATPase (effect increased by co-administration with ICS)

Question 13

Fluticasone, mometasone, budesonide mechanism of action? (ICS)

Answer 13

Directly decrease inflammatory cells like eosinophils, monocytes, mast cells, macrophages and dendritic cells decreasing number of inflammatory cells & cytokines they produce

Question 14

How is budesonide different to other ICS?

Answer 14

Less potent than fluticasone and mometasone

Question 15

Target of fluticasone, budesonide, mometasone?

Answer 15

Glucocorticoid receptor on inflammatory cells

Question 16

Side effects of fluticasone, budesonide, mometasone?

Answer 16

Sore throat, hoarse voice, opportunistic oral infections (oral thrush)

Question 17

Systemic effects of fluticasone, mometasone, budesonide?

Answer 17

Growth retardation in children, hyperglycaemia, decreased bone mineral density, immunosuppression, effects on mood

Question 18

Oral bioavailability of fluticasone?

Answer 18

<1% so inhaled route preferred

Question 19

Affinity of fluticasone compared to cortisol?

Answer 19

Greater affinity for glucacorticoid receptor than cortisol

Question 20

Montelukast type of drug?

Answer 20

Leukotriene receptor antagonist

Question 21

Montelukast mechanism of action?

Answer 21

Antagonist of CystLT1 leukotriene receptor on eosinophils, mast cells & airway smooth muscle cells decreases eosinophil migration, bronchoconstriction & inflammation induced oedema

Question 22

Montelukast target?

Answer 22

CystLT1 leukotriene receptor

Question 23

Montelukast side effects?

Answer 23

Diarrhoea, fever, headache, nausea, vomiting. Mood changes, anaphylaxis.

Question 24

What is montelukast used as prophylaxis for specifically / when is it given?

Answer 24

Prophylaxis of exercise induced bronchoconstriction, administered at least 2h before starting exercise