Approach to treatment of eclamptic seizures

It is unnecessary to routinely check for a therapeutic magnesium level as there does not appear to be a clear threshold concentration for ensuring the prevention of seizures. If the level is checked (eg, recurrent seizure), a therapeutic range of 4.8 to 8.4 mg/dL (2.0 to 3.5 mmol/L) has been recommended based on retrospective data. If magnesium toxicity is suspected (eg, loss of deep tendon reflexes), the maintenance dose should be decreased or eliminated and the magnesium level should be checked. If the serum level is >9.6 mg/dL (8 mEq/L), the infusion should be stopped and serum magnesium levels should be determined at two-hour intervals. The infusion can be restarted at a lower dose when the serum level is <8.4 mg/dL (7 mEq/L). For further information on magnesium dosing and toxicity, refer to UpToDate content on management of preeclampsia and eclampsia.