Levosalbutamol Dosing for Acute Asthma Attack
For adults experiencing an acute asthma attack, administer levosalbutamol 1.25-2.5 mg via nebulizer every 20 minutes for 3 doses, then every 1-4 hours as needed; for children, use 0.075 mg/kg (minimum 1.25 mg) with the same frequency. 1, 2
Adult Dosing Protocol
Nebulized Levosalbutamol
- Initial treatment: 1.25-2.5 mg every 20 minutes for 3 doses 1, 3
- Maintenance: 1.25-5 mg every 1-4 hours as needed based on severity and clinical response 1, 3
- Dilute to minimum 3 mL with normal saline at gas flow of 6-8 L/min for optimal delivery 1
- Key principle: Levosalbutamol is administered at half the milligram dose of racemic salbutamol for equivalent efficacy 1, 2, 4
MDI Alternative (Mild-to-Moderate Exacerbations)
- Dosing: 4-8 puffs (45 mcg/puff = 180-360 mcg total) every 20 minutes for 3 doses, then every 1-4 hours as needed 1, 5
- MDI with valved holding chamber is as effective as nebulized therapy when proper technique is used 1, 3
Pediatric Dosing Protocol
Nebulized Levosalbutamol
- Weight-based: 0.075 mg/kg with absolute minimum of 1.25 mg regardless of calculated dose 1, 2
- Initial treatment: Every 20 minutes for 3 doses 2
- Maintenance: 0.075-0.15 mg/kg every 1-4 hours as needed 2
- Dilute to minimum 3 mL with normal saline 2
MDI Alternative
- Dosing: 4-8 puffs (45 mcg/puff) every 20 minutes for 3 doses 1
- Use valved holding chamber with face mask for children under 4 years 1
Adjunctive Therapy Requirements
Add Ipratropium for Moderate-to-Severe Exacerbations
- Adults: Add ipratropium 500 mcg to nebulizer solution 6, 1
- Children: Add ipratropium 250 mcg 6
- Combined therapy significantly reduces hospitalization rates in severe exacerbations 1
Systemic Corticosteroids (Essential)
- Adults: Prednisolone 30-60 mg orally or hydrocortisone 200 mg IV immediately 6
- Children: 1-2 mg/kg/day (maximum 60 mg/day) 1
- Administer early in moderate-to-severe exacerbations 1
Oxygen Supplementation
- Use oxygen as nebulizer driving gas at 6-8 L/min in acute severe attacks 6
- Simultaneous nasal cannula oxygen at 4 L/min is appropriate 6
Severity Assessment and Treatment Escalation
Severe Attack Features (Requiring Immediate Aggressive Treatment)
- Cannot complete sentences, respiratory rate >25/min, heart rate >110/min, peak flow <50% predicted 6
- Initiate oxygen, systemic steroids, and nebulized levosalbutamol immediately 6
Life-Threatening Features (Consider ICU/Hospital Transfer)
- Peak flow <33% predicted, silent chest, cyanosis, exhaustion, confusion 6
- Normal or elevated PaCO2 in breathless patient, severe hypoxia (PaO2 <8 kPa) 6
- Consider continuous nebulization at 0.5 mg/kg/hour for children or 10-15 mg/hour for adults 1
Critical Clinical Pitfalls to Avoid
Dosing Errors
- Never use equal milligram doses of levosalbutamol and salbutamol - this doubles the beta-agonist effect and increases adverse effects 2
- Always use the minimum dose (1.25 mg) even when weight-based calculations suggest lower amounts in children 2
Response Assessment
- Reassess at 30 minutes: Early response (30-minute PEFR improvement) is the most important predictor of outcome, not initial severity 7
- Approximately 30% of patients show poor response patterns to beta-agonists regardless of dose - these patients need early hospital admission 7
- Response to treatment is a better predictor of hospitalization need than initial exacerbation severity 1
Monitoring Requirements
- Watch for tachycardia, tremor, and hypokalemia with frequent or high-dose administration 1, 2
- Monitor for signs of impending respiratory failure: inability to speak, altered mental status, intercostal retraction, worsening fatigue 1
- Use with caution in cardiovascular disorders, hyperthyroidism, diabetes mellitus, and convulsive disorders 2, 3