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IV Magnesium in Acute Asthma — RACP Paediatrics MCQ

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HardRespiratoryIV Magnesium in Acute AsthmaRACP Paediatrics

A 5-year-old presents with acute wheeze and respiratory distress. He has received 3 doses of salbutamol via spacer and a dose of ipratropium. Symptoms persist. SpO2 is 90%. What is the next pharmacological step?

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Correct answer: E — IV magnesium sulfate

For severe acute asthma not responding to initial bronchodilator therapy, IV magnesium sulfate (0.1-0.2 mmol/kg, max 10 mmol, over 20 minutes) is the next recommended step. It causes smooth muscle relaxation via calcium channel blockade. IV salbutamol infusion is also an option for life-threatening asthma.

Reference: National Asthma Council Australia – 2024 – Australian Asthma Handbook