What are the specific orders for managing preeclampsia (pre-eclampsia)?

From the Guidelines

For pre-eclampsia management, the primary orders include antihypertensive medications to maintain blood pressure below 160/110 mmHg, with labetalol or hydralazine as first-line treatments, and magnesium sulfate for seizure prophylaxis in women with proteinuria and severe hypertension, or hypertension with neurological signs or symptoms, as recommended by the ISSHP classification, diagnosis, and management recommendations for international practice 1.

Key Management Points

• Antihypertensive medications should be used to maintain blood pressure below 160/110 mmHg, with acceptable agents including oral nifedipine or intravenous labetalol or hydralazine 1.
• Women with preeclampsia should be assessed in hospital when first diagnosed, and thereafter, some may be managed as outpatients once it is established that their condition is stable and they can be relied on to report problems and monitor their BP 1.
• Magnesium sulfate should be administered to women with preeclampsia who have proteinuria and severe hypertension, or hypertension with neurological signs or symptoms, for convulsion prophylaxis 1.
• Fetal monitoring in preeclampsia should include an initial assessment to confirm fetal well-being, and serial fetal surveillance with ultrasound should be performed at least every 2 weeks if the initial assessment was normal, and more frequently in the presence of fetal growth restriction 1.
• Maternal monitoring in preeclampsia should include BP monitoring, repeated assessments for proteinuria if not already present, clinical assessment including clonus, and twice weekly blood tests for hemoglobin, platelet count, liver transaminases, creatinine, and uric acid 1.

Delivery Recommendations

• Women with preeclampsia should be delivered if they have reached 37 weeks’ gestation or if they develop any of the following: repeated episodes of severe hypertension despite maintenance treatment with 3 classes of antihypertensive agents; progressive thrombocytopenia; progressively abnormal renal or liver enzyme tests; pulmonary edema; abnormal neurological features, such as severe intractable headache, repeated visual scotomata, or convulsions; or nonreassuring fetal status 1.
• For pregnancies <34 weeks with stable maternal-fetal conditions, antenatal corticosteroids should be administered to accelerate fetal lung maturity, and fluid restriction to 80-100mL/hour is recommended to prevent pulmonary edema 1.

From the FDA Drug Label

In Pre-eclampsia or Eclampsia In severe pre-eclampsia or eclampsia, the total initial dose is 10 to 14 g of magnesium sulfate. Intravenously, a dose of 4 to 5 g in 250 mL of 5% Dextrose Injection, USP or 0. 9% Sodium Chloride Injection, USP may be infused. Simultaneously, IM doses of up to 10 g (5 g or 10 mL of the undiluted 50% solution in each buttock) are given Alternatively, the initial IV dose of 4 g may be given by diluting the 50% solution to a 10 or 20% concentration; the diluted fluid (40 mL of a 10% solution or 20 mL of a 20% solution) may then be injected IV over a period of three to four minutes Subsequently, 4 to 5 g (8 to 10 mL of the 50% solution) are injected IM into alternate buttocks every four hours as needed, depending on the continuing presence of the patellar reflex and adequate respiratory function. Alternatively, after the initial IV dose, some clinicians administer 1 to 2 g/hour by constant IV infusion. Therapy should continue until paroxysms cease A serum magnesium level of 6 mg/100 mL is considered optimal for control of seizures. A total daily (24 hr) dose of 30 to 40 g should not be exceeded.

The specific orders for pre-eclampsia are:

• Initial dose: 10 to 14 g of magnesium sulfate
• IV dose: 4 to 5 g in 250 mL of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP
• IM dose: up to 10 g (5 g or 10 mL of the undiluted 50% solution in each buttock)
• Subsequent doses: 4 to 5 g (8 to 10 mL of the 50% solution) injected IM into alternate buttocks every four hours as needed
• Alternative: 1 to 2 g/hour by constant IV infusion after the initial IV dose
• Therapy should continue until paroxysms cease
• Serum magnesium level: 6 mg/100 mL is considered optimal for control of seizures
• Total daily dose: 30 to 40 g should not be exceeded 2

From the Research

Specific Orders for Pre-Eclampsia

• The management of pre-eclampsia involves the use of various pharmacotherapeutic options, including oral nifedipine, intravenous labetalol, and hydralazine 3, 4, 5, 6.
• According to a study published in 2016, oral nifedipine and intravenous labetalol were found to be effective in reducing blood pressure to target levels in patients with severe pre-eclampsia, with no significant difference in time interval and drug dosages between the two groups 3.
• Another study published in 2009 reviewed the pharmacotherapeutic options for the treatment of pre-eclampsia, including the use of oral methyldopa, intravenous hydralazine, and labetalol, as well as the role of magnesium sulfate in preventing and controlling maternal seizures 4.
• A randomized control trial published in 2022 compared the effectiveness of nifedipine, labetalol, and hydralazine in lowering blood pressure during hypertensive emergencies in severe pre-eclampsia, and found that nifedipine was the most effective drug when a single dose was used, while hydralazine was the most effective when the drug administration was maximized to three doses within 60 minutes with 20 minutes interval 5.
• A study published in 2023 compared the outcomes of intravenous magnesium, intravenous labetalol, and oral nifedipine in 355 pregnant Han Chinese women with pre-eclampsia, and found that intravenous labetalol provided proper reduction of blood pressure, but had the risk of undesirable maternal and neonatal adverse effects 6.
• The diagnosis and management of pre-eclampsia were reviewed in an article published in 2012, which discussed the concept of "atypical" presentation, the identification of women with pre-eclampsia who will have a poorer pregnancy outcome, and the question of when to deliver and how to treat if the pregnancy is to be prolonged 7.

Treatment Options

• Oral nifedipine: effective in reducing blood pressure to target levels in patients with severe pre-eclampsia 3, 5, 6.
• Intravenous labetalol: effective in reducing blood pressure to target levels in patients with severe pre-eclampsia, and provides proper reduction of blood pressure in Han Chinese women with pre-eclampsia, but has the risk of undesirable maternal and neonatal adverse effects 3, 4, 5, 6.
• Hydralazine: effective in lowering blood pressure during hypertensive emergencies in severe pre-eclampsia, and is the most effective when the drug administration is maximized to three doses within 60 minutes with 20 minutes interval 4, 5.
• Magnesium sulfate: used to prevent and control maternal seizures in patients with severe pre-eclampsia or eclampsia, and has a role in the management of pre-eclampsia, but has a short action time and does not provide stable maintenance of blood pressure 4, 6.