Magnesium, Phosphate and Calcium

Organ that excretes magnesium

Kidneys

Magnesium imbalance in renal failure

Hypomagnesaemia: Kidneys excrete magnesium, so it’s retained in renal failure

Symptoms of hypermagnesaemia

Muscle weakness and arrhythmias

Drug treatment for hypermagnesemia

Calcium gluconate injection

Treatment for mild hypomagnesaemia

Oral magnesium

Treatment for symptomatic hypomagnesaemia

IV / IM magnesium sulphate

Hypophosphatemia is more common in which patient groups?

Alcohol dependence. Severe DKA.

Treatment for hypophosphatemia

Oral phosphate supplements

Treatment of hyperphosphatemia in patients with stage 4/5 CKD

Manage diet + dialysis before starting agents

Phosphate binding agents used for hyperphosphatemia

1L: Calcium acetate. 2L: Sevelamer. 3L: Calcium carbonate (calcium-based) or sucroferric oxyhydroxide (non-calcium-based).

How much more of the recommended amount of calcium should patients with osteoporosis receive?

Double recommended amount

Vitamin oral calcium supplements are given with

Vitamin D

Treatment of severe acute hypocalcemia

Initially slow IV calcium gluconate 10% with plasma calcium and ECG monitoring

What condition can occur if calcium gluconate is given too rapidly

Arrhythmias

How to treat severe hypercalcaemia

Correct dehydration first with IV NaCl 0.9% → discontinue drugs causing hypercalcemia. Restrict dietary calcium. → Bisphosphonates and Pamidronate sodium used. Use corticosteroids if due to sarcoidosis/Vit D toxicity)

Drug used in hypercalcaemia associated with malignancy

Calcitonin

Treatment of non-severe hypercalcaemia

Increase fluid intake + give bendroflumethiazide. Reduce dietary calcium (not severe restriction).