If you are hospitalized for preeclampsia, you may be prescribed the drug magnesium sulfate. Magnesium sulfate helps prevent the occurrence of seizures in women with severe preeclampsia and decreases seizures in women with eclampsia (seizure activity). Randomized, controlled trials in women with eclampsia show that women treated with phenytoin (Dilantin) are three times more likely and those treated with diazepam (Valium) are two times more likely to have recurrent seizures, than women treated with magnesium sulfate.

Therefore, as a preventive measure, magnesium sulfate is given to women with severe preeclampsia and eclampsia (or who may develop eclampsia after giving birth). The drug is administered intravenously.

Whether women with mild preeclampsia should be given magnesium sulfate is more controversial. Because magnesium can reduce seizures in preeclamptic women regardless of the severity, some doctors recommend magnesium sulfate for all women with preeclampsia. However, in Western countries, 385 women with mild preeclampsia would need to be treated with magnesium sulfate to prevent one eclamptic seizure. Because of this, many physicians reserve magnesium sulfate for women with severe preeclampsia and eclampsia. Only 63 women with severe preeclampsia would need to be treated to prevent one eclamptic seizure. Because eclamptic seizures may occur after delivery, intravenous magnesium sulfate is continued for at least 24 hours after you give birth. If your blood pressure is extremely elevated, you may be prescribed additional medications. If given intravenously, anti-hypertensive medications can rapidly decrease blood pressure.