What is the recommended furosemide dosing regimen for an adult with acute decompensated heart failure?

Furosemide Dosing in Acute Heart Failure

For acute decompensated heart failure, start with 20–40 mg IV furosemide as a slow bolus (over 1–2 minutes) if the patient is diuretic-naïve, or use a dose at least equivalent to their chronic oral dose if already on loop diuretics, ensuring systolic blood pressure is ≥90–100 mmHg before administration. 1, 2, 3

Initial Dose Selection

• Diuretic-naïve patients or those on ≤40 mg oral furosemide daily should receive 20–40 mg IV bolus administered slowly over 1–2 minutes 1, 2, 3
• Patients on chronic oral diuretics require an initial IV dose that is at least equivalent to their oral daily dose (e.g., if taking 80 mg PO daily, give ≥80 mg IV initially) to overcome diuretic tolerance 1, 2
• Severe volume overload with prior diuretic exposure may warrant starting with 40–80 mg IV based on renal function and severity of congestion 1, 2

Critical Pre-Administration Requirements

Before giving any furosemide dose, verify:

• Systolic blood pressure ≥90–100 mmHg – furosemide worsens hypoperfusion and can precipitate cardiogenic shock in hypotensive patients 1, 2
• Serum sodium >125 mmol/L – severe hyponatremia (<120–125 mmol/L) is an absolute contraindication 1, 2
• Absence of anuria – the patient must have detectable urine output 1, 2
• No marked hypovolemia – assess for signs of volume depletion before administration 1, 2

Dose Escalation Protocol

• If urine output remains <0.5 mL/kg/hour after 2 hours, double the dose but never exceed 160–200 mg per individual bolus 1, 2, 3
• Increase in 20 mg increments every 2 hours until adequate diuresis is achieved 1
• Maximum limits: Do not exceed 100 mg in the first 6 hours or 240 mg in the first 24 hours (though higher doses may occasionally be used with close monitoring) 1, 2

Continuous Infusion vs. Bolus Dosing

Both strategies are equally effective – the European Society of Cardiology gives a Class I, Level B recommendation that diuretics can be given either as intermittent boluses or continuous infusion 2

• Continuous infusion option: After initial 40 mg bolus, infuse at 5–10 mg/hour (maximum rate 4 mg/min) 1, 2
• Continuous infusion may be preferred for patients with significant volume overload, those requiring high doses, or when diuretic resistance develops 1, 2, 4
• Practical advantage of continuous infusion: Provides more stable tubular drug concentrations and may overcome diuretic resistance more effectively than intermittent boluses 1, 4

Evidence Comparison

• A 2014 randomized trial showed continuous infusion (10 mg/hour) produced greater 24-hour diuresis (3705 mL) compared to bolus dosing (3093 mL and 2670 mL for different bolus regimens, p<0.01), though clinical symptom relief was similar across groups 5
• However, continuous infusion was associated with higher rates of hypokalemia (36.3% vs. 13.5% and 8.3%, p<0.01) 5
• A retrospective study of low-dose continuous infusion (<160 mg/24 hours) showed significant increase in urine output (150 vs. 116 mL/hour, p<0.001) without detectable worsening of renal function 4

Essential Monitoring

• Place a bladder catheter to measure urine output hourly and rapidly assess treatment response 1, 2
• Target urine output >0.5 mL/kg/hour as a marker of adequate diuretic response 1, 2
• Check electrolytes (especially potassium and sodium) and renal function within 6–24 hours, then every 3–7 days during active therapy 1, 2
• Monitor blood pressure frequently – both bolus and infusion strategies can cause hypotension 1, 2
• Daily weights targeting 0.5–1.0 kg loss per day 1

Managing Diuretic Resistance

• If adequate diuresis is not achieved after 24–48 hours at standard doses, add a second diuretic class rather than escalating furosemide beyond 160 mg/day 1, 2
• Combination options: Hydrochlorothiazide 25 mg PO, spironolactone 25–50 mg PO, or metolazone 2.5–5 mg PO 1
• Sequential nephron blockade (combining loop diuretic with thiazide or aldosterone antagonist) is more effective than monotherapy escalation 1

Absolute Contraindications Requiring Immediate Cessation

Stop furosemide immediately if:

• Systolic blood pressure drops <90 mmHg without circulatory support 1, 2
• Severe hyponatremia develops (sodium <120–125 mmol/L) 1, 2
• Anuria occurs (no urine output) 1, 2
• Severe hypokalemia develops (potassium <3.0 mmol/L) 1

Common Pitfalls to Avoid

• Do not give furosemide to hypotensive patients expecting hemodynamic improvement – it will worsen tissue perfusion and precipitate shock 1
• Do not under-dose out of fear of worsening renal function – a transient creatinine rise ≤0.3 mg/dL is acceptable in asymptomatic patients, and persistent congestion carries greater risk than mild azotemia 1, 6
• Do not exceed 160 mg/day without adding a second diuretic – higher doses provide no additional benefit due to the ceiling effect 1, 2
• Higher prehospital doses are not harmful – a 2015 study showed patients receiving higher prehospital furosemide doses were actually less likely to experience worsening renal function (adjusted OR 1.49 for each 20 mg decrease, p=0.019) 6