hypomagnesaemia

Common cause Commonly implicated drugs: PPI, diuretics, cyclosporin, laxative misuse, cisplatin; problems with absorption e.g. Crohn's
Clinical presentation Arrhythmia (AF - aim Mg > 1), tremors, confusion, vomiting
Management PO - Mg aspartate, 1-2 sachets OD, or
IV - 5g in 250ml normal saline/5% glucose, or 10g in 500ml normal saline/5% glucose
S/e: diarrhoea; replace with caution in pts with heart block or myocardial damage

Remember avoid in Myasthenia gravis