Magnesium Sulphate therapy in preeclampsia

Continuous Intravenous Infusion

Magnesium sulfate 4-g to 6-g loading dose diluted in 100 mL fluid  administered intravenously over 15 minutes, followed by continuous intravenous infusion at 1 to 2 g per hour. Discontinue 24 hours after delivery or last seizure.

If convulsions persist after 15 min, give up to 2  gram more intravenously as a 20% solution at a rate not to exceed 1g/min. If the woman is large (> 70 kg) then an additional 2 grams may be given slowly

Only give the next IM dose, or only continue the IV infusion if:

Respiratory rate > 16/min
Urine output > 25 ml/h
Patellar reflexes are present

If urine output < 100 ml in 4 h and there are no other signs of magnesium toxicity, reduce the IV infusion to 0.5 g/h.

If patellar reflexes are depressed and respiration is normal, withhold further doses of magnesium sulfate until the reflexes return and request magnesium level.

If there is concern about respiratory depression , stop magnesium, give oxygen by mask and give:

Calcium gluconate (10mL of 10% solution over 10 minutes)

ACOG TASK FORCE 2013

... For women with severe preeclampsia, the administration of intrapartum and postpartum magnesium sulfate to prevent eclampsia is recommended.  For women with preeclampsia undergoing cesarean delivery, the continued intraoperative administration of parenteral magnesium sulfate to prevent eclampsia is recommended.