5th April 2024

Clinical manifestations

Features of hypermagnesaemia depend on approximate serum concentrations: 

• 2.0 -3.5 mmol/L – nausea and vomiting, flushing and ECG changes
• 4.0 – 5.0 mmol/L – hypotension, absent deep tendon reflexes, drowsiness and slurred speech
• > 6.0 mmol/L – respiratory depression, coma and paralytic ileus
• > 8.0 mmol/L – cardiac arrest and complete heart block