Respiratory pharmacology

Question 1

SELECTIVE BETA 2 AGONISTS

i) what do they ultimately cause?
ii) at what dose is neb salbutamol given at? what dose in inhaled given at?
iii) give an eg of a SABA? what is it used for? give two SEs
iv) give an eg of a LABA? how long is onset of action? give two indications

Answer 1

i) smooth muscle of airway relaxation (via stim adenyl cyc > cAMP)
ii) salbutamol nebs at 2.5mg and inhaled at 100 micrograms

iii) SABA = salbutamol or terbutaline
- management of breathlessness
- SEs - tremor, resting sinus tachy, hypokalemia

iv) LABA - formeterol or salmeterol
- onset is 15-45 mins (formet is quicker)
- improves symptoms and FEV1, improvement of exacerbation rate

Question 2

ANTI MUSCARINICS

i) what do they do?
ii) which two receptors does ipotropium block? which receptor is tiotropium selective for?
iii) give an example of a SAMA? what is its onset time?
iv) give an eg of a LAMA
v) name four side effects of anti muscarinics

Answer 2

i) bind to muscarinic receptors in bronchial sm muscle and inhibit Ach release from psym nerve endings

ii) ipo blocks M2 and M3
- tio is selective for M3

iii) SAMA - ipratropium
- onset 30 mins

iv) LAMA is tio
v) headache, dry mouth, disturb to GI motil, poor systemic absorption