What is the recommended nebulised salbutamol (albuterol) dosing regimen for adults and children, including initial doses, repeat intervals, and maximum daily limits?

Nebulised Salbutamol Dosing

For acute asthma exacerbations, administer nebulised salbutamol at 2.5-5 mg every 20 minutes for 3 doses in adults, and 0.15 mg/kg (minimum 2.5 mg) every 20 minutes for 3 doses in children, followed by 2.5-10 mg every 1-4 hours as needed in adults and 0.15-0.3 mg/kg every 1-4 hours as needed in children. 1, 2

Initial Treatment Phase (First Hour)

Adults

• Initial dosing: 2.5-5 mg every 20 minutes for 3 doses 1
• Dilute aerosols to a minimum of 3 mL at gas flow of 6-8 L/min 1, 2
• Can be mixed with ipratropium bromide in the same nebuliser 1, 2

Children (≤12 years)

• Initial dosing: 0.15 mg/kg (minimum dose 2.5 mg) every 20 minutes for 3 doses 1, 2
• Use the same dilution and gas flow parameters as adults 1
• Available concentrations: 0.63 mg/3 mL, 1.25 mg/3 mL, 2.5 mg/3 mL, 5.0 mg/mL 2

Maintenance Dosing (After Initial Hour)

Adults

• Standard maintenance: 2.5-10 mg every 1-4 hours as needed 1, 2
• Continuous nebulisation option: 10-15 mg/hour for severe exacerbations 2
• Frequency should be decreased as symptoms improve 1

Children

• Standard maintenance: 0.15-0.3 mg/kg up to 10 mg every 1-4 hours as needed 2
• Continuous nebulisation option: 0.5 mg/kg/hour for severe cases 2

Severe Exacerbations

For patients with FEV1 or PEF <40% predicted, severe symptoms at rest, or high-risk features:

• Consider hourly or continuous nebulisation of salbutamol 1
• Add ipratropium bromide 0.5 mg (adults) or 0.25-0.5 mg (children) every 20 minutes for 3 doses 1, 2
• Continuous nebulisation at 10-15 mg/hour in adults or 0.5 mg/kg/hour in children may be used 2

Alternative High-Dose Regimens

Research evidence supports higher doses in refractory cases:

• High-dose intermittent: 0.30 mg/kg every hour has shown superior FEV1 improvement compared to 0.15 mg/kg in children 3
• Very high-dose continuous: 75-150 mg/hour (3.7 mg/kg/hour) has been used safely in pediatric intensive care settings with low rates of mechanical ventilation and short PICU stays 4
• These higher doses showed increased heart rate and decreased blood pressure but no severe toxicity requiring intervention 4

Continuous vs Intermittent Nebulisation

Both methods are equally effective - the choice should be based on logistical considerations 5:

• Continuous nebulisation: 15 mg in first hour, then 12.5 mg over next 5 hours 5
• Intermittent nebulisation: 5 mg every 20 minutes for first hour, then 2.5 mg hourly 5
• No significant difference in clinical outcomes, hospitalization rates, or treatment failure 5, 6

Important Caveats

Delivery Considerations

• Oxygen should be used as the driving gas whenever possible in acute severe asthma 7
• Use large volume nebulisers for continuous administration 1, 2
• MDI with spacer (4-8 puffs every 20 minutes) is equally effective as nebulised therapy in mild-to-moderate exacerbations with proper technique 1, 2, 1

Safety Profile

• Salbutamol is safe in children under 2 years, though MDI may be safer than nebulised formulation 8
• Common side effects include tachycardia, tremor, and hypokalemia, but severe adverse effects are rare 4, 9, 3
• Hypokalemia (K+ <3.0 mEq/L) may occur but typically does not require supplementation 4
• No maximum daily dose is specified in guidelines, but dosing should be titrated to clinical response 1, 2

Post-Discharge Management

• Continue salbutamol as needed rather than fixed-dose weaning regimens 10
• This approach reduces salbutamol use by 50-73% without increasing reattendance rates 10
• Initiate or continue inhaled corticosteroids before discharge 1

Contraindications and Interactions

• Avoid in patients on beta-blockers (may cause severe bronchospasm) 11
• Use with extreme caution with MAO inhibitors or tricyclic antidepressants 11
• Monitor digoxin levels in patients on chronic digoxin therapy 11