Therapeutics of asthma

Question 1

Asthma

Answer 1

variation in airflow obstruction and at least 2 of: wheeze, SOB, chest tightness, cough

Question 2

Diagnosis of asthma

Answer 2

Mainly on history but

• tests influence diagnosis
• absence of alternative explanation for symptoms
• objective response to treatment is helpful

Question 3

Triggers of asthma

Answer 3

• allergens - dust mite, pollen
• occupational - isocyanates, wood resin, dyes
• drugs - NSAIDs, Beta blockers
• environment - cold air, emotion, exercise

Question 4

Mechanisms of asthma and how we combat them

Answer 4

• genetic factors
• triggers (avoid)
• inflammation (steroids)
• inflammatory mediators (leukotriene antagonists)
• bronchospasm - B2 agonists/anticholinergics/theophylline

Question 5

Non-pharmacolgical management of asthma

Answer 5

• personalised action plan

- secondary prevention: smoking cessation, weight loss, breathing exercises

Question 6

Selective B2 agonists

Answer 6

• salbutamol and terbutaline
• cause rapid dilation, used when necessary
• inhaler/nebuliser/IV/oral

Question 7

Contraindications and s/e of selective B2 agonists

Answer 7

• no specific CI’s

- s/e are minimal - high doses may cause tremor, tachycardia and hypokalaemia

Question 8

Inhaled corticosteroids

Answer 8

• preventor therapy - reduce inflammation
• beclometasone (800microg/day max), fluticasone, budesonide
• variable potency - prescribe by brand name

Question 9

Adverse effects of inhaled corticosteroids

Answer 9

• sore throat / oral thrush- common
• osteoporosis in adults (high dose)
• growth supression in children

Question 10

How to reduce risk of oral thrush from inhaled corticosteroids

Answer 10

• use spacer device

- rinse mouth / brush teeth after

Question 11

Long acting B2 agonists

Answer 11

• step 3 of asthma therapy
• salmeterol, formoterol
• longer duration of action - 12hours
• relief of reversible airway obstruction
• should always be used with inhaled corticosteroid - available in combination (seretide)

Question 12

Step 4 of asthma therapy

Answer 12

• increase ICS up to highest dose
• addition of LTRA, SR Theophylline, Beta agonist table, LAMA
• refer patient for specialists care

Question 13

Leukotriene Receptor Antagonists - use, drug, CI and s/e

Answer 13

• prophylaxis
• montelekuast 10mg tablet at night
• CI: pregnancy, renal failure
• s/e: hypersensitivity reactions, GI upset

Question 14

Xanthine derivative

Answer 14

• oral modified release theophylline
• non-selective PDE inhibitor - causes bronchial SM relaxation (inhibits reversible airways obstruction)
• dangerous

Question 15

Problems with xanthine derivatives

Answer 15

• drug interactions
• narrow therapeutic index
• variations in liver metabolism
• adverse effects: cardiac arrhythmias, seizures

Question 16

Step 5 of asthma treatment

Answer 16

• continuous/frequent oral steroids
• used for brittle asthma
• try to avoid - risk of adrenal supression and Cushings reactions

Question 17

Management of acute severe asthma in adults

Answer 17

1. Hospital admission and oxygen
2. Nebulised salbutamol or terbutaline
3. Steroid - prednisolone 40-50mg or hydrocortisone 100mg IV
   If response is poor…
4. Muscarinic antagonist - Ipatropium bromide 500microg every 4-6 hours via O2 driven nebuliser
5. IV B2 agonist, magnesium sulphate or aminophylline