Asthma

Question 1

Outline the BTS Asthma Guidelines 
Name an example for each drug class you mention

Answer 1

Step 1 = PRN short acting beta agonist e.g. Salbutamol
Step 2 = add inhaled corticosteroid e.g. Beclomethasone
Step 3 = add a long acting beta agonist, e.g. Salmeterol
Step 4 = add a leukotriene receptor antagonist e.g. Montelukast, or a methylxanthine e.g. Theophylline
Step 5 = daily oral corticosteroid e.g. Prednisolone

Question 2

Outline the 4 major steps in treating acute severe asthma

Answer 2

• High flow O2
• Nebulised salbutamol
• Oral Prednisolone
• Consider IV aminophylline or Nebulised ipratropium bromide

Question 3

Outline the mechanism of action of B2 agonists

Answer 3

• Bind to B2 receptors in the bronchial smooth muscle
• Gs coupled - increase cAMP
• In turn, results in decreased Ca2+ - therefore decreased smooth muscle contraction - hence bronchodilation

Question 4

Compare and contrast the onset and period of action of SABAs and LABAs

Answer 4

SABAs - 
- Onset = 5 - 30mins
- Lasts 4 - 6 hours
LABAs
- Salmeterol slow onset, formeterol rapid
- Last up to 12 hours

Question 5

Which drug must LABAs always be given alongside?

Why?

Answer 5

Inhaled corticosteroids

On their own they increase mast cell degranulation in response to allergens - associated with higher asthma deaths

Question 6

List 4 ADRs of B agonists

Answer 6

• Increased heart rate
• Palpitations
• Tremor
• LABAs - muscle cramps

Question 7

Which class of drug interacts with B-agonists?

Answer 7

B-blockers - blocks effect of B-agonist

Question 8

Give 2 examples of SABAs and 2 examples of LABAs

Answer 8

• SABAs - salbutamol, terbutaline

- LABAs - salmeterol, formeterol

Question 9

Give 3 examples of inhaled corticosteroids

Answer 9

Beclomethasone
Budenoside
Fluticasone

Question 10

Outline the mechanism of action of corticosteroids in relation to their use in asthma

Answer 10

• Cross plasma membrane, bind to cytoplasmic receptor, receptor complex into nucleus
• Modifies transcription of several genes:
• Increased expression of anti inflammatory proteins
• Decreased expression of ILs, cytokines, chemokines
• Therefore decreased inflammation and mucus - hence widened airways

Question 11

Give 2 common ADRs of inhaled corticosteroids. What could you do to reduce these?

Answer 11

• Oral candidiasis
• Hoarse voice
• Use a spacer

Question 12

Name 2 methylxanthines

Answer 12

Theophylline and aminophylline

Question 13

What is the mechanism of action of methylxanthines in very broad terms?

Answer 13

Antagonise adenosine receptors

Question 14

List 4 ADRs of methylxanthines

Answer 14

• Nausea
• Headache
• Arrhythmias
• Fits

Question 15

Name an example of a leukotriene receptor antagonist

Answer 15

Montelukast

Question 16

Briefly describe the mechanism of action of leukotriene receptor antagonists

Answer 16

• Block leukotriene CysLT1 receptor - block effect of cysteinyl leukotrienes
• Therefore cause bronchodilation and decreased mucus production

Question 17

What class of drug are tiotropium bromide and ipratropium?

Answer 17

Long acting Muscarinic antagonists (anti-muscarinics)

Question 18

What is the mechanism of action of antimuscarinic agents?

Answer 18

Block M3 receptors - decrease smooth muscle tone and decrease mucus production