Pharmacology of COPD and Asthma

Question 1

What are some examples of short acting bronchodilators?

Answer 1

• Beta 2 agonists,
• Inhaled ipratropium bromide,
• Theophylline

Question 2

Describe the mechanism of action, indications, side effects of B2 agonists

Answer 2

• Highly specific for pulmonary receptors vs cardiac receptors. Increases intracellular cAMP which causes relaxation of bronchial smooth muscle.
• Indicated in asthma and COPD,
• Side effects include tremor, hypokalaemia, hyperglycaemia, flushing, tachycardia, arrhythmias, headaches

Question 3

Describe the mechanism of action, indications, side effects of corticosteroids

Answer 3

• Suppress pro-inflammatory genes.
• Indicated in asthma, COPD with reccurent exacerbations and in the exacerbations of assthm/copd.
• Several side effects including: Diabetes, osteoporosis, hypertension, cataracts, cushing’s syndrome, immune supression

Question 4

What is MART therapy?

Answer 4

A single inhaler which is used for maintenance AND reliever therapy

Question 5

Name some examples of leukotriene receptor antagonists and their mechanism of action

Answer 5

Montelukast. They inhibit the action of leukotrienes in smooth muscle cells of the airway and therefore reduce airway oedema and SM contraction

Question 6

Describe the mechanism of action, indications, side effects and examples of anti-muscarinics

Answer 6

• Antagonist of M1 and M3 receptors, counteracting the broncho-constriction which occurs with muscarinic receptor activation.
• Indicated in asthma and COPD.
• Side effects include- blurred vision, dry mouth, urinary retention.
• Short acting = ipratropium bromide. Long acting = Tiotropium

Question 7

Describe the mechanism of action, indications, side effects and examples of methylxanthines

Answer 7

• Inhibit phosphodiesterase which increases intracellular cAMP and causes bronchial SM relaxation. Also improves mucocilliary clearance and has anti-inflammatory effects.
• It is used as an adjunctive in severe asthma exacerbations.
• Side effects include GI upset and palpitations.
• Examples are aminophylline or theophylline

Question 8

What are some of the pharmacokinetic properties of methylxanthines?

Answer 8

• It has a very narrow theraputic window of 10-20mg/L so requires extensive monitoring. Weight-based dosing is used for IV infusion.

Question 9

Name a monoclonal antibody that can be used in asthma

Answer 9

• These are used in patients with a high corticosteroid burden. For example, Omalizumab (used in allergic asthma), Mepolizumab is used in eosinophilic asthma

Question 10

What is are the SIGN guidelines for the step-wise approach to asthma management?

Answer 10

1. Give short acting Beta agonists.
2. Add a low dose ICS,
3. Add a LABA (or increase ICS)
4. Add a LTRA (or increase ICS to medium dose)
5. Refer for specalist care

Question 11

What are the clinical signs of life threatening asthma?

Answer 11

• Altered conscious level,
• Exhaustion,
• Arrhythmia,
• Hypotension,
• Cyanosis,
• Silent chest,
• Poor resp effort

Question 12

What is the management of life threatening asthma?

Answer 12

• Give oxygen to maintain SpO2,
• Nebulised bronchodilators,
• Oral prednisolone (to reduce bronchial inflammation)
• Consider oral doxycycline if chest infection is suspected.
• IV magnesium (blocks histamine release from mast cells and diminishes Ach)
• Consider IV aminophylline infusion (only in life threatening or near fatal asthma)

Question 13

What is the pharmacological management of COPD with/without asthmatic features?

Answer 13

Without - LAMA and LABA.
With - LABA and ICS.
If there is no improvement consider add a 3rd treatment which will either be a LAMA or ICS depending what they are already on.

Question 14

Name an example of a mucolytic and when it is used

Answer 14

Carbocystine, it is only used when a patient has a productive cough and COPD.