Please check your internet connection and try again.
# Furosemide (Lasix)
## Overview
Furosemide is a potent loop diuretic used to manage fluid overload (edema) and high blood pressure. It works by inhibiting sodium and chloride reabsorption in the loop of Henle, leading to increased excretion of water and electrolytes.
## Primary Indications
* Edema associated with congestive heart failure (CHF), liver cirrhosis, and renal disease.
* Hypertension, typically as an adjunct therapy.
## Adult Dosing
* **Edema:**
* Oral: Start with 20-80 mg once daily. Higher doses may be needed, up to 600 mg daily in divided doses for severe cases. Dosing should be individualized and adjusted based on response.
* Intravenous (IV) or Intramuscular (IM): Start with 20-40 mg once daily. If inadequate response, doses can be increased by 20 mg every 2 hours. Continuous IV infusion may be used in severe cases.
* **Hypertension:**
* Oral: Start with 40 mg twice daily. Adjust based on response. Furosemide is generally not a first-line agent for hypertension.
## Pediatric Dosing
* **Edema:**
* Oral: 1-2 mg/kg per dose once or twice daily. Maximum initial dose is 40 mg per day. Doses can be increased by 1-2 mg/kg every 6-8 hours as needed.
* IV/IM: 1 mg/kg per dose once or twice daily. Maximum initial dose is 20 mg per day. Doses can be increased by 1 mg/kg every 2 hours as needed.
* **Neonates:** Dosing may vary. A common regimen is 1 mg/kg/dose IV every 12-24 hours, or 0.5-1 mg/kg/dose PO every 12-24 hours. Dosing for premature neonates may differ; consult specialized pediatric resources.
## Dose Adjustments
* **Renal Impairment:** Higher doses may be required due to decreased renal excretion. However, caution is advised as it can also worsen renal function. Dose titration should be cautious.
* **Hepatic Impairment:** May require dose adjustments due to altered metabolism and increased sensitivity to electrolyte imbalances.
## Contraindications
* Anuria.
* Known hypersensitivity to furosemide or sulfonamides.
* Severe electrolyte depletion (e.g., hyponatremia, hypokalemia).
## Adverse Effects
* **Common:** Dizziness, lightheadedness, electrolyte imbalances (hypokalemia, hyponatremia, hypochloremia, hypomagnesemia, hypocalcemia), dehydration, hypotension, increased urination, gout.
* **Less Common:** Ototoxicity (especially with rapid IV administration or high doses), hyperglycemia, rash, pruritus, blood dyscrasias.
## Key Drug Interactions
* **Aminoglycosides:** Increased risk of ototoxicity and nephrotoxicity.
* **Other Diuretics (Thiazides, Potassium-Sparing):** Additive effects, increased risk of dehydration and electrolyte disturbances.
* **NSAIDs:** Can reduce natriuretic and antihypertensive effects. May increase risk of renal impairment.
* **Lithium:** Furosemide can decrease lithium clearance, increasing the risk of lithium toxicity.
* **Antihypertensives:** Additive hypotensive effects.
* **Corticosteroids:** Increased risk of hypokalemia.
* **Digoxin:** Risk of digoxin toxicity is increased due to furosemide-induced hypokalemia.
## Monitoring
* Electrolytes (sodium, potassium, chloride, magnesium, calcium) regularly, especially at initiation or dose changes.
* Renal function (BUN, creatinine).
* Blood pressure.
* Fluid status (weight, intake/output).
* Blood glucose in diabetic patients.
* Uric acid in patients with a history of gout.
## Clinical Pearls
* Furosemide is a potent diuretic; monitor fluid and electrolyte status closely.
* Rapid IV administration can increase the risk of ototoxicity. Administer IV doses slowly over 30-60 minutes or as an infusion.
* Edematous patients, particularly those with hepatic cirrhosis or ascites, may be more resistant to furosemide and require higher doses.
* For patients with edema, dosing frequency may be adjusted to once daily or every other day to allow for electrolyte repletion.
***
*This information is intended for clinical professionals and is not a substitute for professional medical advice. Always verify current prescribing information with the manufacturer's package insert or other reliable sources before making clinical decisions.*
