Furosemide

General

  • Type: Diuretic
  • Dosage Forms:20, 40, 80
  • Common Trade Names: Lasix
  • Approximately 50% bioavailability, so converting from oral to IV dose doubles oral dose[1]
  • Furosemide absorption may be reduced in decompensated CHF[2]

Adult Dosing

40 mg furosemide = 20 mg torsemide = 1 mg bumetanide = 50 mg ethacrynic acid

  • Fluid overload: Typically 40 mg IV or normal PO dosage IV
  • hypertension: 10-40 mg PO QDAY-BID, max 600 mg/day
  • Hypercalcemia: 120 mg/day PO divided QDAY - TID
  • Continuous infusion may increase diuresis effect and minimize post-diuretic sodium retention and "diuretic braking"[3]
    • Start 0.1 mg/kg/hr, increase hourly to max of 0.75 mg/kg/hr[4]
    • Target > 1 mL/kg/hr
    • Monitor for ototoxicity

Pediatric Dosing

Special Populations

  • Pregnancy Rating:C
  • Lactation: safety unknown
  • Renal Dosing
    • Adult: no adjustment, contraindicated in anuria
    • Pediatric: no adjustment, contraindicated in anuria
  • Hepatic Dosing
    • Adult: not defined
    • Pediatric: not defined

Contraindications

  • Allergy to class/drug
  • anuria
  • electrolyte imbalances

Adverse Reactions

Serious

  • hypokalemia
  • metabolic alkalosis
  • hypovolemia
  • ototoxicity
  • hemolytic anemia
  • vasculitis
  • steven-johnson syndrome
  • pancreatitis
  • eosinophilia

Common

  • urinary frequency
  • dizziness
  • nausea/vomiting
  • weakness
  • muscle cramping
  • hypokalemia
  • hypomagnesemia
  • blurred vision
  • diarrhea
  • hyperglycemia
  • hyperuricemia
  • tinnitus

Pharmacology

  • Half-life: 30-60 min
  • Metabolism: liver minimally
  • Excretion: urine
  • Mechanism of Action: inhibits loop of henle and proximal and distal convoluted tubule sodium and chloride resorption

See Also

References

  1. Asare K. Management of Loop Diuretic Resistance in the Intensive Care Unit. Am J Health Syst Pharm. 2009;66(18):1635-1640.
  2. Vasko MR, Brown-Cartwright D, Knochel JP et al. Furosemide absorption is altered in decompensated congestive heart failure. Ann Intern Med. 1985; 102: 314–8.
  3. Pivac N, Rumboldt Z, Sardelic S et al. Diuretic effects of furosemide infusion versus bolus injection in congestive heart failure. Int J Clin Pharmacol Res. 1998; 18:121–8.
  4. Schuller D, Lynch JP, Fine D. Protocol-guided diuretic management: comparison of furosemide by continuous infusion and intermittent bolus. Crit Care Med. 1997; 25:1969–75.