Respiratory drugs

Question 1

What do short acting Beta-2 agonists (SABA) do?

Answer 1

Act on beta -2 receptors
Cause smooth muscle relaxation and dilate the airways
Rapid onset
effects last for up to 4 hours
Less lipophilic

Question 2

what do Leukotriene receptor antagonists do?

Answer 2

Bronchodilation + anti-inflammatory effects
LTRAs reach maximal plasma conc within 3 hours
half-life can be up to 10 hours

Question 3

What do Methylxanthines do?

Answer 3

Example: Theophylline
Bronchodilator
Has a reverse resistance to corticosteroids
active in CNS,CVS and GI
-MOA: Inhibits Phosphodiesterase enzyme so high levels of cAMP are maintained, MLCK inactivated, myosin not phosphorylated, so bronchial smooth muscle relaxation
-ADR: CNS + CVS, nervousness, insomnia, seizures

Question 4

What do long acting Beta-2 agonists(LABA) do?

Answer 4

Act directly on beta-2 receptors
causes smooth muscle relaxation and dilate airways
rapid onset is also possible
effects can last up to 12 hours
More lipophilic

Question 5

What is hydrophobicity?

Answer 5

Tendency of non-polar groups of a molecule to aggregate in order to minimise the unfavourable exposition to the surrounding polar solvent (water).

Question 6

What is Lipophilicity?

Answer 6

A measure of affinity if a molecule for the non-polar solvent in a biphasic system constituted by a polar and non-polar solvent

Question 7

What do Long-acting muscarinic receptor antagonists do (LAMA)?

Answer 7

• used to treat asthma
• has more selectivity for M3 receptor
  -more lipophilic
  -onset of action 30 mins - lasts 24 hours
  -e.g. tiotropium
• quaternary nitrogen compounds

Question 8

What do Short-acting muscarinic receptor antagonists do (SAMA)?

Answer 8

• Used to treat asthma
• Act on M2 and M3 receptors (non-selective) in the parasympathetic ns (vagus nerve)
• onset of action 15 mins - lasts 3-5 hours
• drugs are less lipophilic
  -e.g. Ipratropium bromide
• bronchodilators
  -quaternary nitrogen compounds
  -ADR include dry mouth + GI tract effects