6.6: Respiratory Therapeutics (Asthma & COPD)

Respiratory Therapeutics in Australian Practice

In Australia, the management of asthma is guided by the National Asthma Council's Australian Asthma Handbook, while chronic obstructive pulmonary disease (COPD) is managed using the COPD-X Plan (developed by the Lung Foundation Australia and TSANZ). Pharmacists play a pivotal role in stepwise therapy optimization, inhaler device selection, technique counselling, and acute exacerbation management.

1. Stepwise Asthma Management (Adults & Adolescents)

The Australian Asthma Handbook emphasizes a major paradigm shift: SABA-only therapy (e.g. salbutamol alone) is no longer recommended as the sole treatment for asthma in adults and adolescents. Regular or frequent SABA use without an inhaled corticosteroid (ICS) increases the risk of severe exacerbations and asthma-related death due to untreated airway inflammation.

Stepwise Pharmacotherapy Algorithm (Age ≥ 12 Years)

• Step 1 (Mild Asthma): Preferred option is as-needed low-dose budesonide-formoterol (e.g., Budesonide-formoterol 200/6 mcg, one inhalation as-needed for symptoms). This provides rapid bronchodilation via formoterol (which has an onset of action as fast as salbutamol) combined with the anti-inflammatory controller budesonide, reducing the risk of severe exacerbations by 60% compared to SABA alone.
• Step 2: Preferred options are regular daily low-dose ICS (e.g., fluticasone propionate 100 mcg daily) plus as-needed SABA, OR as-needed low-dose budesonide-formoterol for symptom relief.
• Step 3: Preferred option is maintenance and reliever therapy (MART) using a low-dose ICS-formoterol combination (e.g., budesonide-formoterol 100/6 or 200/6, 1-2 inhalations daily plus as-needed for symptoms), OR regular maintenance low-dose ICS-LABA (e.g., fluticasone furoate-vilanterol) plus as-needed SABA.
• Step 4: Preferred option is medium-dose ICS-formoterol MART, OR regular maintenance medium-dose ICS-LABA plus as-needed SABA.
• Step 5: Maintenance high-dose ICS-LABA plus add-on therapies (such as the LAMA tiotropium, or biologic agents like omalizumab for allergic asthma, mepolizumab for eosinophilic asthma). Refer to a specialist.

Pediatric Stepwise Management (Children ≤ 5 Years)

In children aged 5 years and under, SABA (salbutamol) via a pressurised metered-dose inhaler (pMDI) with a spacer remains the preferred reliever therapy.

• Step 1: As-needed SABA.
• Step 2: Daily preventer therapy with low-dose ICS (e.g., fluticasone propionate 50 mcg BD) or oral montelukast.
• Note: ICS-formoterol as-needed is not recommended or approved for children under 12 years of age in Australia.

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2. Chronic Obstructive Pulmonary Disease (COPD) Management

COPD is characterized by persistent, progressive respiratory symptoms and airflow limitation that is not fully reversible. Management is guided by the COPD-X guidelines.

Diagnosis

Spirometry is required to confirm COPD diagnosis: a post-bronchodilator FEV1/FVC < 0.70.

Stepwise Pharmacotherapy

Pharmacotherapy aims to optimize function, prevent symptoms, and reduce exacerbations.

1. Mild Symptoms / Intermittent Dyspnoea: Short-acting bronchodilator as-needed — either a SABA (salbutamol) or a SAMA (ipratropium).
2. Persistent Symptoms (Step Up): Long-acting bronchodilator — either a LAMA (e.g., tiotropium, glycopyrronium) or a LABA (e.g., indacaterol, salmeterol). LAMAs are generally preferred over LABAs for their superior efficacy in reducing exacerbation rates.
3. Severe Symptoms / Frequent Exacerbations (Step Up): Dual long-acting bronchodilator therapy (LAMA + LABA, e.g., glycopyrronium-indacaterol, umeclidinium-vilanterol).
4. Triple Therapy (LAMA + LABA + ICS): Reserved for patients who experience recurrent exacerbations (e.g., ≥ 2 moderate exacerbations or ≥ 1 leading to hospitalization in the past year) despite dual LAMA + LABA therapy, and who have blood eosinophils ≥ 300 cells/microliter or a history of asthma.
   • Important Trap: ICS monotherapy is contraindicated in COPD because it increases the risk of pneumonia without providing clinical benefit.

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3. Inhaler Device Selection & Technique Counselling

Device selection and correct technique are critical for therapeutic success. Pharmacists must assess and train patients on their devices at every opportunity.

Device Comparison

ICS Counselling

For all ICS-containing inhalers (including MART therapies), patients must rinse their mouth with water and spit it out after use. This prevents local adverse effects, including oral candidiasis (thrush) and dysphonia (hoarseness).

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4. Acute Exacerbation Management

Acute Asthma Exacerbation (Moderate-to-Severe)

1. Bronchodilators: Salbutamol via pMDI + spacer: 4-12 puffs, repeating every 20 minutes for the first hour if necessary.
2. Systemic Corticosteroids: Oral prednisolone (30-50 mg daily for 5-7 days for adults; 1 mg/kg up to 50 mg daily for children for 3-5 days).
3. Oxygen: Maintain target SpO2 of 93-95% (92-95% in pregnant patients).

Acute COPD Exacerbation

1. Bronchodilators: Salbutamol (2-6 puffs) via pMDI + spacer every 2-4 hours. Ipratropium may be added.
2. Systemic Corticosteroids: Oral prednisolone (30-50 mg daily for 5 days). Long courses do not offer extra benefit and increase side effects.
3. Controlled Oxygen: Target oxygen saturation of 88-92%. High-flow oxygen must be avoided in patients with COPD, as it can cause hypoventilation, hypercapnia, and respiratory acidosis due to loss of their hypoxic drive.
4. Antibiotics: Indicated only if the patient has signs of clinical infection, defined by at least two cardinal symptoms (increased dyspnoea, increased sputum volume, or increased sputum purulence).
   • First-line: Amoxicillin 500 mg three times daily for 5 days, OR Doxycycline 200 mg on Day 1, then 100 mg daily for a total of 5 days.