Magnesium Sulphate in pregnancy

INDICATION	Prevention of eclamptic fit Abort eclamptic fit Fetal neuroprotection following preterm birth
ADMINISTRATION	IV: 4g slow bolus over 10 minutes as loading dose, followed by 1-2 g/hour Sulphate maintenance infusion given via a controlled infusion pump. IM: 4g IV slow bolus over 10 minutes, followed immediately by 10g IM, then 5 g IM every 4 hours in alternate buttock. RECURRENT SEIZURE: 2 - 4g of MgSO4 is given over 5-10 minutes. MAXIMUM INFUSION RATE 4g/hr To be infused <150mg/min
MONITORING	Looking for signs of toxicity (especially loss of deep tendon reflexes, respiratory depression with rate <16/minute) and renal impairment (hourly urine output <30 ml/hour).
ANTIDOTE	Calcium Gluconate 1g in 10 mL (2.2mmol Calcium in 10mL) over 3 to 10min

When MgS04 is administered it should be continued for 24 hours following birth, or for 24 hours after the last seizure

Before discontinuation of MgSO4 therapy:

• the blood pressure should be stable (consistently below 150/100)
• the patient should have adequate diuresis
• the patient should be clinically improved (absence of headache, epigastric pain).

REFERENCES

1. Malaysian CPG Management of Hypertension 4^th edition

2. King Edward Memorial Hospital Guideline, Jan 2015

3. Queen Elizabeth Dilution Protocol Guideline