Drugs Affecting the Respiratory System

Question 1

What is Omalizumab?

Answer 1

A humanised murine monoclonal antibody that binds to IgE and prevents it from binding to FcER1

• over time get a decrease in the amount of IgE and FcER1
• administered subcutaneously
• expensive

Question 2

What are the three classes of H1 receptor antagonists?

Answer 2

Sedative - entry into CNS
Non-sedative - no entry into CNS, withdrawn due to causation of rare, sudden ventricular arrhythmia
Newer non-sedative - no entry into CNS, reduced risk of unwanted cardiac events

Question 3

How is smooth muscle tone regulated?

Answer 3

Calcium oscillations –> MLC -> phosphorylation to MLC-P, increasing contraction
PKA -> turns off contractile mechanism
Rho kinase and PKC inhibit the inhibition –> activate the process more

Question 4

What are relievers?

Answer 4

Short acting beta-2-adrenoceptor agonists (SABA)

• salbutamol, terbutaline
• short acting - rapid 2-5 min onset
• beta-2 selective, get reduced activation of MLCK
• adverse effects of tachycardia, tremor and hypokalaemia

Question 5

What are controllers?

Answer 5

Long acting beta-2-adrenoceptor agonists (LABA)
- salmeterol - slow onset, 12 hrs duration
- formoterol - rapid onset, 12 hrs duration
- indacaterol - rapid onset, 24hrs duration (once daily)
used for prophylaxis
- reduce number of exacerbations
- used in combination with inhaled GCS
* tolerance develops

Question 6

What are muscarinic receptor antagonists?

Answer 6

Ipratropium bromide
- non-selective, short acting, SAMA
Tiotropium bromide
- functionally M3 selective, LAMA

Less effective than beta-2 agonists in asthma, more effective in COPD

Question 7

What is the function of glucocorticoids in asthma?

Answer 7

Decrease inflammatory cell number and activation
Decrease probability and severity of an episode of asthma
BROAD ANTI-INFLAMMATORY EFFECT

Question 8

What is the mechanism of action of glucocorticoids?

Answer 8

Bind to receptor in cytoplasm, move to nucleus

• dimerise –> transcription factor –> upregulate expression of anti-inflammatory agents
• monomer, associated with NFkB –> no expression of pro-inflammatory genes

Question 9

When are glucocorticoids used in the treatment of asthma?

Answer 9

Inhaled - for mild, persistent asthma
- when need a beta-2 agonist more than 3 times a week
- budesonide, fluticasone propionate
- start at effective dose and step down
Systemic
- prednisolone (not being controlled by usual dose of inhaled)

Question 10

What is the effect of glucocorticoids on endogenous cortisol production?

Answer 10

Adrenal glands undergo atrophy and production of cortisol is reduced.
If patient stops treatment could go into adrenal crisis because they will take a while to restore

Question 11

When are glucocorticoids indicated for asthma?

Answer 11

• for mild, persistent asthma

- when need a beta 2 agonist greater than 3 times a week