Mg2+

Electrolyte Navigator — Magnesium

CDMtools · thinnest primary-care sourcing of the four — verify locally throughout
Draft · verify locally

Hypomagnesaemia

Mg<0.7 mmol/L — admission decision first, then cause

↓

Hypermagnesaemia

Mg>1.1 mmol/L — rare, almost always renal or iatrogenic

↑

Patient values

Normal range ~0.7–1.0 mmol/L
Risk flags
Symptomatic: confusion, weakness, ataxia, tetany, tremor, fasciculations, arrhythmia
Cause pointers
GI losses: diarrhoea, malabsorption, stoma
On loop diuretic or long-term PPI
Alcohol excess or poor nutritional intake
On cisplatin, EGFR inhibitor, ciclosporin, or tacrolimus

Pathway

Click any step on the pathway above for bedside and lab assessment cues.

Interpretation

Enter a magnesium value to begin routing.

Patient values

Normal range ~0.7–1.0 mmol/L
Risk flags
Loss of tendon reflexes (early red flag)
Respiratory depression, severe hypotension, arrhythmia, or bradycardia
Context
Renal impairment or failure
Recent magnesium-containing antacid, laxative, or supplement use

Pathway

Click any step on the pathway above for bedside and lab assessment cues.

Interpretation

Enter a magnesium value to begin routing.

CDMtools — Electrolyte Navigator (pilot). Draft thresholds — verify locally against current guidance before clinical use. Magnesium has the thinnest UK primary-care source base of the four electrolytes in this suite — treat thresholds here as more provisional than sodium/potassium/calcium. Click any underlined term for its definition and source.