Please check your internet connection and try again.
# Furosemide
## Overview
Furosemide is a potent loop diuretic used to reduce fluid overload.
## Primary Indications
* Edema associated with heart failure, liver cirrhosis, and renal disease (including nephrotic syndrome).
* Hypertension (although not typically first-line).
## Adult Dosing
* **Edema:** Oral: Initial dose 20-80 mg once daily. May increase by 20-40 mg every 6-8 hours or daily. Usual maintenance: 40-80 mg once daily. Maximum oral dose: 600 mg/day (higher doses may be used in rare, severe cases under close monitoring).
* Intravenous (IV) or Intramuscular (IM): Initial dose 20-40 mg once daily. May increase by 20 mg every 2 hours or daily. Usual maintenance: 40-80 mg once daily. Maximum IV/IM dose: 600 mg/day (higher doses may be used in rare, severe cases under close monitoring).
* **Hypertension:** Oral: 40 mg twice daily (typically reserved for patients with concomitant edema or heart failure).
## Pediatric Dosing
* **Edema:**
* Oral: 1-2 mg/kg/dose once daily. May increase dose every 6-8 hours by 1-2 mg/kg/dose. Maximum dose: 6 mg/kg/day.
* IV/IM: 1 mg/kg/dose once daily. May increase dose every 2 hours by 1 mg/kg/dose. Maximum dose: 6 mg/kg/day. Doses higher than 2 mg/kg may be necessary in neonates or infants with impaired renal function.
## Dose Adjustments
* **Renal Impairment:** Dose may need to be increased in patients with severe renal impairment due to reduced renal clearance and protein binding. However, caution is advised as higher doses may be less effective and increase the risk of ototoxicity. Continuous infusions may be more effective than intermittent boluses.
* **Hepatic Impairment:** Cirrhosis with ascites: Oral doses are generally similar, but IV doses may be less effective due to altered pharmacokinetics.
## Contraindications
* Anuria.
* Hypersensitivity to furosemide or sulfonamides.
* Severe electrolyte depletion (e.g., hyponatremia, hypokalemia).
## Adverse Effects
* **Electrolyte imbalances:** Hypokalemia, hyponatremia, hypochloremia, hypomagnesemia, hypocalcemia.
* **Dehydration and hypotension.**
* **Ototoxicity** (especially with rapid IV administration or high doses).
* Hyperuricemia (may precipitate gout).
* Hyperglycemia.
* Dizziness, lightheadedness.
* Rash, photosensitivity.
* Oliguria.
## Key Drug Interactions
* **Aminoglycosides and other ototoxic drugs:** Increased risk of ototoxicity.
* **Digoxin:** Increased risk of digoxin toxicity due to furosemide-induced hypokalemia.
* **Antihypertensives:** Additive hypotensive effects.
* **NSAIDs:** May reduce diuretic and antihypertensive effects, and increase risk of renal impairment.
* **Lithium:** Reduced renal clearance of lithium, increasing risk of lithium toxicity.
* **Corticosteroids:** Increased risk of hypokalemia.
## Monitoring
* Electrolytes (sodium, potassium, chloride, magnesium, calcium).
* Renal function (BUN, creatinine).
* Fluid status (weight, intake/output).
* Blood pressure.
* Uric acid and glucose (especially in predisposed patients).
* Hearing (especially with high doses or IV administration).
## Clinical Pearls
* Furosemide is a potent diuretic; monitor for signs of dehydration and electrolyte depletion.
* Administer IV furosemide slowly (over at least 30-60 minutes) to reduce the risk of ototoxicity and flushing. For very high doses (>80mg), consider continuous infusion.
* Oral and IV doses are not always equivalent; IV doses are typically about half the oral dose.
* Monitor for tinnitus or hearing loss, which may indicate ototoxicity.
* Correct hypokalemia before or concurrently with furosemide therapy if possible, or consider potassium-sparing diuretics or supplementation.
---
*Disclaimer: This information is intended for educational purposes only and does not constitute medical advice. Always consult the most current prescribing information and a healthcare professional for any medical decisions.*
