Advice
Evidence: economic issues
Cost effectiveness
No studies on the cost effectiveness of oral magnesium glycerophosphate for preventing recurrent hypomagnesaemia after intravenous infusion were identified.
Cost
According to the Drug Tariff, December 2012:
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magnesium glycerophosphate oral solution (magnesium 24.25 mg/ml, equivalent to 1 mmol/ml) costs £176.48 for 200 ml
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magnesium glycerophosphate oral suspension (magnesium 24.25 mg/ml equivalent to 1 mmol/ml) costs £147.61 for 150 ml.
For an adult, the BNF states that 24 mmol Mg2+ daily can be given to prevent recurrence of magnesium deficit. This daily dose would cost £21.18 for the oral solution or £23.62 for the oral suspension based on the Drug Tariff.
The Prescription Cost Analysis for the NHS in England reported that the cost of magnesium glycerophosphate 97.2 mg tablets (equivalent to 4 mmol magnesium) ranged between £0.42 and £1.38 per tablet. Capsules were more expensive, costing £2.04 per 97.2 mg capsule and £2.70 per 48.6 mg capsule.
To provide a dosage of 24 mmol Mg2+ daily, 6 tablets or capsules of magnesium glycerophosphate 97.2 mg, or 12 capsules of magnesium glycerophosphate 48.6 mg, would be needed. Based on the costs above, this would cost between £2.52 and £8.28 per day for tablets and between £12.24 and £32.40 per day for capsules (excluding VAT, dispensing costs and fees).
Current drug usage
The Prescription Cost Analysis for the NHS in England reported that 25,900 community prescriptions for oral magnesium glycerophosphate were dispensed in 2011, costing £3,795,200 (net ingredient cost [NIC]). Information on the indications for which these prescriptions were being used is not available from the Prescription Cost Analysis report.
The most commonly prescribed magnesium glycerophosphate preparations were chewable 97.2 mg tablets (10,000 prescription items prescribed and dispensed by proprietary brand name), followed by non-chewable 97.2 mg tablets (9300 items prescribed and dispensed generically).