What are the common indications and normal adult dose for furosemide (Lasix) in patients with conditions such as congestive heart failure, cirrhosis of the liver, nephrotic syndrome, and hypertension?

Furosemide: Common Indications and Normal Adult Dosing

FDA-Approved Indications

Furosemide is FDA-approved for treating edema associated with congestive heart failure, cirrhosis of the liver, renal disease (including nephrotic syndrome), and hypertension in adults. 1

---

Standard Adult Dosing by Indication

Congestive Heart Failure

Acute Decompensated Heart Failure:

• Initial dose: 20-40 mg IV bolus over 1-2 minutes 2
• For patients already on chronic oral furosemide >40 mg/day at home, start with 80 mg IV rather than 40 mg 2
• Maximum total dose should remain <100 mg in the first 6 hours and <240 mg during the first 24 hours 2
• If inadequate response, double the dose rather than giving repeated small doses 2

Chronic Heart Failure:

• Starting dose: 20-40 mg orally once daily in the morning 2, 3
• May be given as 20-40 mg once or twice daily depending on response 2
• Maintenance doses typically range from 20-80 mg/day 3
• Doses exceeding 160 mg/day indicate advanced disease requiring treatment escalation or combination therapy 2

Cirrhosis with Ascites

Initial regimen: Furosemide 40 mg combined with spironolactone 100 mg as a single morning dose 2

• Maintain the 100:40 spironolactone-to-furosemide ratio when escalating 2
• Increase both drugs simultaneously every 3-5 days if weight loss <2 kg/week 2
• Maximum furosemide dose: 160 mg/day (exceeding this indicates diuretic resistance requiring paracentesis) 2
• Oral administration is strongly preferred over IV to avoid acute GFR reduction 2

Nephrotic Syndrome

Severe edema:

• Starting dose: 0.5-2 mg/kg per dose IV or orally, up to six times daily 2
• Maximum: 10 mg/kg per day 2
• High doses (>6 mg/kg/day) should not be given for periods longer than 1 week 2
• May administer IV furosemide 0.5-2 mg/kg at the end of albumin infusions in the absence of marked hypovolemia or hyponatremia 2

Hypertension

• Typical dose: 40 mg twice daily initially 1
• May be used alone or in combination with other antihypertensive agents 1
• Note: Patients inadequately controlled with thiazides will likely not be controlled with furosemide alone 1

---

Critical Dosing Considerations

Route of Administration

• IV administration is preferred in acute situations requiring rapid diuresis 2
• Oral administration has variable bioavailability (especially in edematous states) but is preferred for chronic management in cirrhosis 2, 4
• Infusions >250 mg must be given over 4 hours to prevent ototoxicity 2

Monitoring Requirements

• Target weight loss: 0.5 kg/day without peripheral edema; 1.0 kg/day with peripheral edema 2
• Check electrolytes (sodium, potassium) every 3-7 days during initial titration 2
• Monitor renal function and blood pressure regularly 2
• Place bladder catheter in acute settings to assess hourly urine output 2

Absolute Contraindications

• Systolic blood pressure <90 mmHg without circulatory support 2
• Marked hypovolemia or anuria 2
• Severe hyponatremia (serum sodium <120-125 mmol/L) 2
• Severe hypokalemia (<3 mmol/L) 2

Common Pitfalls to Avoid

• Never give furosemide to hypotensive patients expecting hemodynamic improvement—it worsens tissue perfusion 2
• Avoid evening doses as they cause nocturia and poor adherence without improving outcomes 2
• In acute pulmonary edema, furosemide should not be used as monotherapy; concurrent IV nitroglycerin is superior 2
• When reaching ceiling doses (80-160 mg/day), add a second diuretic class (thiazide or aldosterone antagonist) rather than further escalating furosemide alone 2

Peak Effect and Duration

• Peak diuretic effect occurs within 1-1.5 hours after oral administration 2
• Duration of action is only 6-8 hours, which may necessitate twice-daily dosing for sustained effect 2
• The maximal diuretic effect occurs with the first dose, with subsequent doses showing up to 25% less effect 2