Paediatric Asthma Medicines

Asthma in children is chronic airway inflammation with variable airflow obstruction. Treatment has two parts: relief of acute episodes with short-acting bronchodilators and systemic corticosteroids, and prevention with inhaled corticosteroids. Under 5 years the diagnosis is based on recurrent wheeze that responds to treatment.

Severity of an acute episode. Moderate: SpO2 94% or more, talking, no distress. Severe: SpO2 under 92%, too breathless to talk or feed, heart rate over 140/min (2 to 5 years) or over 125/min (over 5 years), respiratory rate over 40 or over 30/min. Life-threatening: SpO2 under 92% with silent chest, cyanosis, poor effort, exhaustion or confusion.

Acute episode:

• Oxygen: target SpO2 94 to 98% by mask or nasal prongs.
• Salbutamol by metered dose inhaler and spacer: 2 to 10 puffs of 100 mcg (one puff at a time, 5 breaths each), repeated every 20 minutes for 1 hour, then as needed.
• Nebulised salbutamol 2.5 mg (under 5 years) or 5 mg (5 years and over) every 20 minutes for 3 doses if severe, with oxygen-driven delivery.
• Ipratropium bromide nebulised: 250 mcg (under 12 years) or 500 mcg (12 years and over) every 20 minutes for 3 doses in severe disease.
• Prednisolone 1 to 2 mg/kg orally once daily (maximum 40 mg) for 3 to 5 days, started within the first hour. No taper is needed for a course under 10 days.
• Alternative to prednisolone: dexamethasone 0.6 mg/kg single oral dose (maximum 16 mg), repeated at 24 hours if needed.
• Magnesium sulphate 40 to 50 mg/kg intravenously over 20 minutes (maximum 2 g) for severe or life-threatening asthma not responding to nebulised treatment.
• Specialist rescue: salbutamol intravenous 15 mcg/kg over 10 minutes (maximum 250 mcg) then 1 to 2 mcg/kg/min, or aminophylline 5 mg/kg intravenously over 20 minutes (omit if on theophylline) with levels.

Prevention:

• Inhaled corticosteroid for symptoms on 3 or more days a week or one exacerbation needing oral steroid: low dose (for example beclometasone equivalent 100 to 200 mcg daily), through a spacer, with mouth rinsing.
• Step up: medium dose inhaled corticosteroid, or add a long-acting beta agonist in the same device (not alone) in children over 5 years.
• Alternatively add montelukast 4 mg (6 months to 5 years) or 5 mg (6 to 14 years) at night.

Technique. Use a spacer with face mask under 3 years, and with mouthpiece from 3 to 4 years. Check technique at every visit, because poor technique is the commonest cause of failure.

Infants under 1 year. Bronchodilator response is poor in bronchiolitis, so do not give routine bronchodilators.

Hypokalaemia. High-dose salbutamol lowers potassium, so check it in severe episodes.

Montelukast. Warn about sleep disturbance, mood change and aggression, and stop if they occur.

Special groups. Adolescents need advice on smoking, vaping and adherence. In East Africa, indoor smoke, biomass fuel and limited inhaler supply are common, and salbutamol tablets or syrup are poor substitutes for inhaled therapy.

Monitoring. Reassess every 20 minutes in the first hour: SpO2, respiratory rate, heart rate and work of breathing. After discharge, follow up within 48 hours for the written action plan. Measure height yearly on inhaled corticosteroids.

Referral and escalation. Escalate for SpO2 under 92% after initial treatment, silent chest, exhaustion, no response to 3 doses of nebulised bronchodilator, or need for intravenous bronchodilator. Admit to a high-dependency area.

Stopping. Step down the inhaled corticosteroid by 25 to 50% after 3 months of control. Oral steroid courses over 10 days need a taper.