Respiratory Drugs

Question 1

How do B2-adrenoceptor agonists work?

Give examples of short & long acting

Answer 1

Act on B2 adrenergic receptor;

• Activates adenylyl cyclase
• ATP → cAMP
• Activates PKA
• → Bronchodilation

Short acting include Salbutamol, Terbutaline

Long acting include Salmeterol, Formoterol

Question 2

How do anticholinergics work?

Give examples

Answer 2

They are muscarinic antagonists, inhibiting bronchial mucus secretion.

eg Ipratropium, Tiotropium

Question 3

How do methylxanthines work?

Give examples

Answer 3

Inhibit phosphodiesterase

• Stops cAMP → AMP conversion
• Increasing cAMP
• Activates more PKA → bronchodilation

eg Theophylline, Aminophylline

Question 4

How do glucocorticoids work?

Give examples

Answer 4

Bind to glucocorticoid receptor, modifying gene transcription;

• Inhibit COX2, cytokines, cell adhesion molecules
• Upregulate anti-inflam genes
• Inhibit IL4,5,13 release from T_H2 cells

eg Beclometasone, Fluticasone, Prednisolone

Question 5

How do Cromones work?

Give examples

Answer 5

Stablise mast cell & inhibit sensory nerves (block Cl^- channel)

eg Sodium Cromoglycate, Nedocromil

Question 6

How do anti-leukotriene’s work?

Give example

Answer 6

Inhibit 5-lipoxygenase (an enzyme that converts arachidonic acid to Leukotriene A₄)

• eg Zileuton

Antagonist for CysLT1 (a receptor for Leukotrienes)

• eg Zafirlukast, Montelukase

Question 7

How do anti-IgE therapies work?

Give examples

Answer 7

Omalizumab

• Humanized monoclonal anti-human IgE
• Neutralizes circulating IgE
• Suppresses allergic reactions, including chronic allergy underlying asthma