MAGNESIUM SULFATE

Dosage should be individualised according to patient’s needs and responses. Plasma levels should also be monitored throughout therapy. 5ml/minute of a 10% solution or its equivalent. Up to 40g MgSO4 (equivalent to 160mmol Mg2+) by slow intravenous infusion (in glucose 5%) over up to 5 days, may be required to replace the deficit (allowing for urinary losses).

Mild magnesium deficiency 1g intramuscularly every 6 hours for 4 doses. Severe magnesium deficiency Up to 250mg/kg intramuscularly given within a period of 4 hours or 5g/litre of infusion solution intravenously over 3 hours Paedriatric population It is recommended that the solution be diluted to 20% w/v prior to intramuscular injection Elderly No special recommendation except in renal impairment, see below Renal impairment: Dosage should be reduced in renal impairment.

Plasma magnesium concentrations should be monitored throughout therapy b) To prevent further seizures associated with eclampsia: An initial intravenous (IV) loading dose is followed for 24h by either an IV infusion, or regular intramuscular (IM) injections.

Intramuscular Maintenance Regimen A loading dose of 4g MgSO4 (approx. 16mmol Mg2+) IV (usually in 20% solution) over 5min (minimum, preferably 10-15 min) is followed immediately by 5g MgSO4 (approx. 20mmol Mg2+) (usually in 50% solution) as a deep IM injection into the upper outer quadrant of each buttock.

Maintenance therapy is a further 5g MgSO4 (approx. 20mmol Mg2+) IM every 4h, continued for 24h after the last fit (provided the respiratory rate is >16/min, urine output >25ml/h, and knee jerks are present). Intravenous Maintenance Regimen A loading dose of 4g MgSO4 (approx.

16mmol Mg2+) IV (or in some cases 5g MgSO4 (approx. 20mmol Mg2+) IV), as described above, is followed by an infusion of 1g/h continued for 24h after the last fit.

Recurrent Convulsions:

In both the IM and IV regimens, if convulsions recur, a further 2-4g MgSO4 (approx. 8 - 16mmol Mg2+) (depending on the woman’s weight, 2g MgSO4 (approx. 8mmol Mg2+) if less than 70Kg) is given IV over 5 min. * The Eclampsia Trial Collaborative Group (Duley L et al) (1995) Which anticonvulsant for women with eclampsia?

, The Lancet, Vol. 345, pp. 1455-1463. Appropriate reductions in dosage should be made for patients with renal impairment; a suggested dose reduction in severe renal impairment is a maximum of 20g MgSO4 (approx. 80mmol Mg2+) over 48 hours.

Hypersensitivity reactions. Hypocalcaemia. Pain or burning at the injection site following IV/IM administration. Hypermagnesaemia characterised by flushing, sweating, thirst, hypotension, drowsiness, dizziness, headache, risk of itching and tingling, nausea, vomiting, confusion, slurred speech, double vision, loss of tendon reflexes due to neuromuscular blockade, muscle weakness, respiratory depression, electrolyte/fluid abnormalities (hypophosphataemia, hyperosmolar dehydration), ECG changes (prolonged PR, QRS and QT intervals), bradycardia, tachycardia cardiac arrhythmias, coma and cardiac arrest.

6). Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard.

Magnesium sulfate must be used with caution in patients suspected of or known to have renal impairment. Magnesium sulfate should not be used in hepatic coma if there is a risk of renal failure. Parenteral magnesium salts should be used with caution in patients with myasthenia gravis.

Serum calcium levels should be routinely monitored in patients receiving magnesium sulfate.

1. Magnesium sulfate is contraindicated in patients with severely impaired renal function.