Furosemide (Lasix) Administration Guidelines
Furosemide should be administered for specific indications including edema associated with congestive heart failure, cirrhosis, renal disease, and hypertension, but should be used judiciously due to potential adverse effects on renal function and electrolyte balance. 1
Indications for Furosemide Use
- Heart Failure: For treatment of edema associated with congestive heart failure
- Liver Cirrhosis: For management of ascites (Grade 2 or 3)
- Renal Disease: Including nephrotic syndrome
- Hypertension: Alone or in combination with other antihypertensive agents
- Cerebral Edema: As adjunctive short-term therapy (not for long-term use)
Dosing Recommendations
Adults:
- Initial dose: 20-80 mg as a single dose
- Maintenance: Same dose can be repeated after 6-8 hours or increased by 20-40 mg increments
- Maximum dose: Up to 600 mg/day in severe edematous states
- Optimal administration: Often most effective when given on 2-4 consecutive days each week 1
Pediatric patients:
- Initial dose: 2 mg/kg body weight as a single dose
- Adjustment: May increase by 1-2 mg/kg if response inadequate
- Maximum dose: Not to exceed 6 mg/kg body weight 1
Monitoring Requirements
- Vital signs: Blood pressure and heart rate
- Weight: Daily monitoring with target weight loss of ≤0.5 kg/day in patients without edema 2
- Laboratory tests:
- Serum electrolytes (particularly potassium)
- BUN and creatinine
- Serum calcium and magnesium
- Urine and blood glucose in diabetic patients 1
Precautions and Contraindications
Use with caution in:
- Patients with hypoproteinemia (e.g., nephrotic syndrome) - reduced efficacy and increased ototoxicity
- Patients with diabetes mellitus - may increase blood glucose levels
- Patients at high risk for radiocontrast nephropathy - may worsen renal function
- Patients with systemic lupus erythematosus - potential exacerbation 1
Discontinue furosemide in cases of:
- Hepatic encephalopathy
- Hyponatremia below 120 mmol/L despite water restriction
- Acute kidney injury
- Lack of response with appropriate low-salt diet 2
Combination Therapy Considerations
- Heart Failure: Combination with nitrates is recommended for moderate-to-severe pulmonary edema rather than aggressive diuretic monotherapy 2
- Liver Cirrhosis: Aldosterone antagonists (spironolactone) are the mainstay of diuretic treatment, with furosemide added as combination therapy 2
- Avoid concurrent use with:
- Ethacrynic acid (increased ototoxicity)
- Aminoglycoside antibiotics (increased ototoxicity)
- High-dose salicylates (increased salicylate toxicity)
- Cisplatin (increased ototoxicity and nephrotoxicity)
- Lithium (reduced renal clearance, increased toxicity) 1
Adverse Effects to Monitor
- Fluid and electrolyte disturbances: Most common adverse reactions
- Transient worsening of hemodynamics: Increased systemic vascular resistance and left ventricular filling pressures for 1-2 hours after administration 2
- Ototoxicity: Especially with rapid IV administration or when combined with other ototoxic drugs
- Hyperuricemia: May precipitate gout
- Glucose intolerance: May worsen diabetes control 1
Special Considerations
- In cerebral edema, furosemide (40 mg) should only be used as adjunctive therapy and not long-term 2
- For diagnostic purposes (Lasix scan), furosemide is used to differentiate between true mechanical obstruction and non-obstructive dilation of the collecting system 3
- In patients with liver cirrhosis, oral administration is standard, and intravenous use is not recommended due to risk of kidney damage from sudden fluid loss 2
Furosemide is a potent loop diuretic that requires careful monitoring and dose adjustment based on patient response. While effective for managing fluid overload, its use must be balanced against potential adverse effects on renal function and electrolyte balance.