magnesium citrate: clinical use

Prescribing considerations

• Confirm the indication and investigate causes of magnesium depletion, including medicines, diabetes and relevant endocrine disease.
• Oral magnesium citrate is not first-line management for severe symptomatic hypomagnesaemia; urgent specialist assessment and parenteral replacement may be required.
• Assess renal function and use caution in cardiac conduction disorders.
• Bioavailability and gastrointestinal tolerability vary between magnesium salts; review patients carefully when switching preparations.

Contraindications and cautions

• Hypersensitivity to magnesium citrate or an excipient.
• Severe renal impairment.

Monitoring

• Monitor serum magnesium according to clinical need, particularly in younger patients and those with renal impairment.
• Assess renal function and clinical features of magnesium accumulation.
• Check for associated hypocalcaemia and hypokalaemia when magnesium deficiency is confirmed.
• Review persistent diarrhoea or fatigue and consider excessive magnesium exposure.

Clinical pharmacology

Magnesium citrate dissociates into physiological magnesium and citrate ions. Intestinal absorption is slow, incomplete and influenced by magnesium status. Magnesium is distributed mainly within bone and tissues and is eliminated principally through the kidneys.

Formulation and product differences

• The selected product is an oral, scored tablet; the score assists swallowing and does not create equal portions.
• A powder for oral solution may be preferable when tablets cannot be swallowed.
• Different magnesium preparations are not automatically interchangeable because bioavailability and tolerability can differ.

Tablet

Route: Oral

Strengths: 97 mg, 4 mmol