Is Lasix (furosemide) suitable for maintaining blood pressure in an eclampsia patient?

Lasix (Furosemide) is NOT Recommended for Blood Pressure Maintenance in Eclampsia

Furosemide should not be used as a primary antihypertensive agent for blood pressure control in eclampsia patients, as diuretics are contraindicated in pre-eclampsia/eclampsia due to already reduced plasma volume and utero-placental perfusion. 1, 2

Why Diuretics Are Contraindicated in Eclampsia

• Plasma volume is already pathologically reduced in pre-eclampsia and eclampsia, making diuretic use potentially harmful by further decreasing intravascular volume and compromising utero-placental blood flow 1, 2

• Utero-placental circulation perfusion is already compromised in these patients, and diuretics can worsen fetal growth retardation by further reducing placental perfusion 1

• The European Society of Cardiology explicitly states that diuretics should not be used as plasma volume is already reduced in preeclampsia 2

Appropriate Blood Pressure Management in Eclampsia

First-Line Antihypertensive Agents

The target blood pressure in eclampsia is <160/105 mmHg or systolic 140-150 mmHg with diastolic 90-100 mmHg 1, 2

Recommended first-line agents include:

• Intravenous labetalol: 20 mg IV bolus, then 40 mg after 10 minutes, followed by 80 mg every 10 minutes to maximum 220 mg 1, 2

• Intravenous nicardipine: Start at 5 mg/h, increase by 2.5 mg/h every 5-15 minutes to maximum 15 mg/h 2

• Oral nifedipine (immediate-release): 10-20 mg orally, repeat in 30 minutes if needed, though this should be avoided when IV access is available due to risk of uncontrolled hypotension, especially when combined with magnesium sulfate 1

Essential Concurrent Treatment

• Magnesium sulfate is mandatory for seizure control: loading dose of 4-5g IV over 5 minutes, followed by maintenance infusion of 1-2g/hour for 24 hours after the last seizure 2

• Avoid combining magnesium sulfate with calcium channel blockers due to risk of severe hypotension 2

Limited Role of Furosemide: Postpartum Only

Furosemide has a role ONLY in the postpartum period, NOT during active eclampsia management:

• Postpartum furosemide (40 mg/day orally for 5 days) can accelerate blood pressure normalization after delivery in women with severe preeclampsia, reducing mean systolic and diastolic pressures and time to blood pressure control 3

• A randomized trial showed that furosemide 20 mg daily plus nifedipine postpartum reduced the need for additional antihypertensives compared to nifedipine alone (8% vs 26%, p=0.017) 4

• Antenatal use of IV furosemide as an adjunct showed no benefit in the first hour but reduced 2-hour systolic blood pressure, suggesting only limited utility in specific volume-overload scenarios 5

Critical Exception: Pulmonary Edema

The only indication for diuretics in eclampsia is when complicated by pulmonary edema or cardiac/renal failure:

• Nitroglycerin (glycerol trinitrate) is the drug of choice for pre-eclampsia associated with pulmonary edema: IV infusion starting at 5 mcg/min, increased every 3-5 minutes to maximum 100 mcg/min 1

• Furosemide has been used safely in pregnancy complicated by renal or cardiac failure, but this is distinct from routine blood pressure management 1

Common Pitfalls to Avoid

• Never use diuretics as primary antihypertensive therapy in active pre-eclampsia/eclampsia due to volume depletion concerns 1, 2

• Avoid sodium nitroprusside except as absolute last resort due to risk of fetal cyanide toxicity with prolonged use 1, 2

• Do not use IV hydralazine as first-line despite its historical popularity, as it is associated with more maternal hypotension, placental abruption, maternal oliguria, and fetal tachycardia compared to other agents 1

• Delivery is the definitive treatment for eclampsia after maternal stabilization 2