FUROSEMIDE

Furosemide, Frusemide DBL, Lasix

 Reviewed by NICU and Dept. of Pharmacy
November 2011
Administration Newborn Drug Protocol Index Newborn Services Home Page

Dose and Administration

  1. Intravenous and oral dosing
      Route Dose Dose Interval (hr)
    <32 weeks IV 1mg/kg/dose 24
    Oral 1-2mg/kg/dose 24
    ≥32 weeks IV 1mg/kg/dose 12-24
    Oral 1-2mg/kg/dose 12-24

 

  1. Intraveous Infusion
    Commence at 0.1 mg/kg/hour, then double the dose every 2 hours until urine output > 1 ml/kg/hour. An aggressive yet controlled diuresis is usually achieved with a dose below 0.4 mg/kg/hour1. However, higher doses up to maximum of 1 mg/kg/hour have been used in infants.

    Usual dilution 50mg/kg furosemide to make 50ml with glucose 5% or glucose 10%. 1ml/hour = 1mg/kg/hour.

Indications

  1. Fluid overload (iatrogenic, congestive heart failure, renal failure, other).
  2. Chronic lung disease.

Contraindications and Precautions

  1. Known hypersensitivity to furosemide.
  2. Caution in preterm infants, especially extreme immaturity.
  3. Caution in infants with renal impairment.
  4. Caution in infants with jaundice.
  5. Caution in infants with hyponatraemia and/or hypokalaemia.

Clinical Pharmacology

Furosemide is a potent loop diuretic with rapid action. The drug inhibits chloride reabsorption in the ascending limb of the Loop of Henle and inhibits tubular sodium transport, causing major loss of sodium and chloride. Increased urinary losses of potassium, calcium and phosphate (large doses only) also occur. Urine pH increases. Furosemide also increases renal blood flow.

Furosemide is rapidly absorbed from the gastrointestinal tract (bioavailability 60-70%). The half life in adults is 2 hours, but this is approximately 8 times greater in neonates.  It is approximately 99% bound to plasma proteins, and excreted mainly unchanged by the kidneys.

Possible Adverse Effects 2,3

  1. Dehydration, hypotension.
  2. Gastrointestinal disturbance (oral administration).
  3. Hyponatraemia, hypokalaemia, hypochloraemic metabolic alkalosis.
  4. Hypercalciuria, hypocalcaemia, nephrocalcinosis.
  5. Rash.
  6. Ototoxicity (especially in those also receiving nephrotoxic drugs).
  7. Nephrotoxicity.

Drug Interactions

Aminoglycosides

  • Possible nephrotoxicity and ototoxicity with high dose furosemide infusions.

Bilirubin

  • Furosemide and bilirubin may displace either other from plasma protein.

Captopril

  • Monitor renal function in infants with renal arterial stenosis.

Ceftazidime

  • May increase ceftazadime levels.

Digoxin

  • Monitor digoxin and potassium levels.

Hydrocortisone

  • May lead to a decrease in potassium levels.

Indomethacin

  • Decrease in effect of furosemide.

Pancuronium

  • Possible increase in neuromuscular blockade.

Phenytoin

  • Decrease in furosemide effect.

Special Considerations

  1. Monitor sodium, potassium and chloride; monitor calcium with long term term use and pH with frusemide infusion. Electrolyte aberrations occur frequently and should be anticipated and monitored.
  2. Dosing regime determined by clinical response and infant's maturity.
  3. Placement of an indwelling urinary catheter should be mandatory for infants receiving continuous infusions of furosemide.