Salbutamol Syrup Dosing for a 3-Month-Old Infant (7.420 kg)
For a 3-month-old infant weighing 7.420 kg, administer salbutamol syrup 0.74-1.11 mg (0.15 mg/kg/dose) orally, which equals approximately 0.37-0.56 mL of standard 2 mg/5 mL syrup, given 3-4 times daily as needed for bronchodilation.
Weight-Based Calculation
- The standard pediatric dosing for oral salbutamol is 0.1-0.15 mg/kg/dose, given 3-4 times daily 1
- For this 7.420 kg infant:
- Minimum dose: 0.1 mg/kg × 7.420 kg = 0.74 mg per dose
- Maximum dose: 0.15 mg/kg × 7.420 kg = 1.11 mg per dose
Volume Conversion for Standard Syrup
- Standard salbutamol syrup concentration is 2 mg/5 mL 1
- Volume calculation:
- For 0.74 mg: (0.74 mg ÷ 2 mg) × 5 mL = 1.85 mL (minimum dose)
- For 1.11 mg: (1.11 mg ÷ 2 mg) × 5 mL = 2.78 mL (maximum dose)
- Practical dosing: Start with 2 mL (0.8 mg) per dose, which can be increased to 2.5-3 mL if needed for adequate bronchodilation 1
Dosing Frequency and Maximum Daily Dose
- Administer every 6-8 hours (3-4 times daily) as needed 1
- Maximum daily dose should not exceed 0.6 mg/kg/day, which equals 4.45 mg/day for this infant 1
- This allows for 4 doses of approximately 1 mg each if needed
Critical Safety Considerations
- Infants under 6 months have limited safety data for oral salbutamol, so careful monitoring for tachycardia, tremor, and restlessness is essential 1
- Systemic absorption from oral administration is higher than inhaled routes, increasing risk of cardiovascular side effects (tachycardia, palpitations) 2
- Monitor heart rate before and after administration; hold dose if resting heart rate exceeds 180 bpm in this age group 1
Route Selection Rationale
- While nebulized salbutamol provides superior bronchodilation with fewer systemic effects 3, 2, oral syrup is appropriate when:
- Nebulizer equipment is unavailable
- The infant cannot tolerate mask administration
- Mild-to-moderate bronchospasm is present rather than severe acute asthma 3
- For severe bronchospasm or acute asthma exacerbation, nebulized salbutamol (0.15 mg/kg, minimum 2.5 mg) is strongly preferred over oral administration 3, 2
Common Pitfalls to Avoid
- Do not confuse syrup concentration: Verify you have 2 mg/5 mL formulation, as other concentrations exist internationally 1
- Avoid regular scheduled dosing without reassessment: Salbutamol should be used as needed for bronchospasm, not as maintenance therapy in infants 1
- Do not exceed maximum daily dose: Cumulative doses above 0.6 mg/kg/day significantly increase tremor and tachycardia risk 2