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Furosemide

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Dose and administration

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


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

  • Fluid overload (iatrogenic, congestive heart failure, renal failure, other).
  • 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

  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 regimen 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.

Management of Furosemide administration

Description

IV Preparation

  • Clear solution 10mg/ml in 2 ml ampoules. Osmolality 287 mOsm/kg, pH 8 - 9.3
  • Do not use if the solution is a yellow colour.

Oral Preparation

Use Lasix ® brand, containing frusemide 10 mg/ ml in 30 ml bottles

Prescription

  • Stat IV and oral doses are charted on stat page of prescription chart in mg/dose.
  • Maintenance doses are charted on prescription chart in mg/dose.

Continuous infusion

Charted on fluid chart giving:

  • rate in ml/hour.
  • dose in mg/kg/hour.

Also charted on drug chart under "continuous infusion" giving:

  • amount of drug to be added.
  • type and volume of base fluid.
  • note dose as mg/kg/ml.

Administration

Slow IV Injection

  1. Dilution is not required.
  2. Administer by slow IV injection over 5 minutes. Filter prior to administration through a 0.2 micron Pall in-line filter.
  3. Do NOT mix with other drugs, IV solution, blood or blood products.
  4. Always flush with sodium chloride 0.9% after IV drug administration to prevent precipitation when mixing with drugs of low pH.

Continuous IV Infusion

  1. Compatible with 0.9% sodium chloride (preferred diluent) , glucose 5 % and glucose 10%
  2. Administer via a syringe pump. Change fluid and tubing every 24 hours. Do not use discoloured solutions.
  3. Incompatible with dobutamine, dopamine, gentamicin and other aminoglycosides, midazolam, milrinone and morphine8. Other drug compatibilities should be checked with ward pharmacist.

Oral

Preferably give one hour prior to feeds. The presence of food may decrease bioavailability.1

Nursing considerations

  1. Assess for signs of adverse effects.
  2. Assess IV site carefully for signs of extravasation.
  3. Record weight, B.P. and pulse rate. Record urine output accurately, especially for infants on continuous infusions.
  4. Measure serum electrolytes, blood glucose, SBR.

Storage

IV preparation Oral solution
Store at room temperature <25°C Store in refrigerator. Do not freeze
Protect from light Discard 3 weeks from opening

References

  1. Phelps SJ, Hak EB, Crill CM, editors. Teddy bear book: Pediatric injectable drugs. 8th ed. Bethesda, MD: American Society of Heath-System Pharmacists; 2007.
  2. Sweetman S (ed.). Martindale: the extra pharmacopoeia, 2005.
  3. Hey, E, editor. Neonatal formulary. 5th ed. Oxford: Blackwell Publishing; 2007
  4. Martin, J, Managing editor. BNF for children 2010-2011. London: BMJ Group, Pharmaceutical Press & RCPCH Publications Ltd; 2010.
  5. Trissel LA. Handbook on Injectable Drugs. American Society of Health-System Pharmacists (ASHP) 16th Edition.
  6. Young TE, Mangum B, editors. Neofax: A manual of drugs used in neonatal care. 18th ed. Raleigh, North Carolina, USA: Acorn Publishing; 2005.

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Document Control

  • Date last published: 30 November 2011
  • Document type: Drug Dosage Guideline
  • Services responsible: ADHB Pharmacy, Neonatology
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years