What is the recommended dose of Salbutamol (albuterol) for reversibility testing in Chronic Obstructive Pulmonary Disease (COPD)?

Salbutamol Dose for Reversibility Testing in COPD

For bronchodilator reversibility testing in COPD, administer 2.5–5 mg of nebulized salbutamol and measure spirometry 15 minutes after administration. 1

Recommended Dosing Protocol

The British Thoracic Society explicitly recommends the following protocol for reversibility testing:

• Administer 2.5–5 mg nebulized salbutamol (or 5–10 mg terbutaline as alternative) 1
• Measure spirometry before and 15 minutes after administration 1
• The dose should be selected to be high on the dose-response curve to ensure adequate drug delivery 1
• Nebulizer delivery is preferred to ensure the medication has been properly inhaled 1

Alternative Delivery Method

• If nebulizer unavailable: Give similar dose via multiple inhalations from metered dose inhaler with large volume spacer 1
• This is less convenient but acceptable if proper technique is ensured 1

Pre-Test Requirements

Patients must be clinically stable and medication-free for appropriate washout periods:

• No short-acting bronchodilators for 6 hours 1
• No long-acting β-agonists for 12 hours 1
• No sustained-release theophyllines for 24 hours 1
• Free from acute infection 1

Interpretation Criteria

Significant reversibility is defined as BOTH of the following:

• FEV₁ increase >200 ml AND >15% from baseline 1
• This threshold exceeds natural variability of FEV₁ and represents the most established definition of reversibility 1

Prognostic Value

• Post-bronchodilator FEV₁ is the best predictor of long-term prognosis 1
• Document results clearly in medical records for future reference 1

Critical Clinical Caveats

A negative FEV₁ response does NOT exclude clinical benefit:

• Patients may still experience improved walking distance or reduced breathlessness despite no FEV₁ change 1
• Research demonstrates that 27 patients initially classified as "irreversible" by acute salbutamol testing later showed significant bronchodilation with continued use 2
• Therefore, beta-2 agonist treatment should always be trialed regardless of reversibility test results 2

Alternative Outcome Measures

Consider measuring lung volumes in addition to FEV₁:

• Research shows 39/40 COPD patients demonstrated clinically significant increases in lung volumes (SVC, FVC, or IC ≥10% predicted) after salbutamol, while only 13/40 showed significant FEV₁ increase 3
• Assessment based solely on FEV₁ underestimates bronchodilator effects 3
• Changes in inspiratory capacity may better reflect reduction in dynamic hyperinflation 3

Diagnostic Objectives

Reversibility testing serves two key purposes:

1. Diagnostic: Identify patients whose FEV₁ increases substantially, suggesting asthma rather than pure COPD 1
2. Prognostic: Establish baseline post-bronchodilator FEV₁ as marker for future treatment assessment 1

Dose-Response Considerations

While the guideline recommends 2.5–5 mg for standardized testing:

• Research shows wide individual variation in optimal bronchodilator dose 4
• Only 22% of patients required >1 mg to achieve 90% maximal bronchodilation 4
• The majority (61%) achieved 90% maximal effect with ≤0.6 mg 4
• However, standardized high-dose testing (2.5–5 mg) ensures you are on the flat part of the dose-response curve for all patients 1