Please check your internet connection and try again.
# Lasix (Furosemide)
## Overview
Furosemide is a potent loop diuretic that inhibits the Na-K-2Cl symporter in the thick ascending limb of the loop of Henle, promoting the excretion of sodium, water, chloride, magnesium, and calcium.
## Primary Indications
* Edema associated with congestive heart failure (CHF), hepatic cirrhosis, and renal impairment (including nephrotic syndrome).
* Management of hypertension.
## Adult Dosing
* **Edema:** Initial oral dose 20–80 mg once daily. If response is inadequate, increase in increments of 20–40 mg no sooner than 6–8 hours after the previous dose until the desired effect is achieved.
* **Maintenance:** May be dosed once or twice daily; clinical response determines the subsequent dose.
* **Maximum:** Up to 600 mg/day has been used in severe cases, but doses >80 mg/day require careful clinical monitoring.
* **Hypertension:** 40 mg twice daily.
## Pediatric Dosing
* **General:** Initial oral dose 2 mg/kg/dose once daily. Increase by 1–2 mg/kg/dose as needed, no more frequently than every 6–8 hours.
* **Maximum:** 6 mg/kg/dose.
## Dose Adjustments
* **Renal Impairment:** No specific adjustment required for patients with chronic kidney disease, but patients with anuria are non-responsive. Higher doses may be required in severe renal failure.
* **Hepatic Impairment:** Use with caution; initiate at the low end of the dosing range to prevent hepatic encephalopathy or electrolyte imbalance.
## Contraindications
* Anuria.
* History of hypersensitivity to furosemide or sulfonamides.
* Severe hypovolemia or dehydration.
* Severe electrolyte depletion (hypokalemia, hyponatremia).
* Hepatic coma or severe electrolyte imbalance until the condition is corrected.
## Adverse Effects
* **Common:** Polyuria, dizziness, orthostatic hypotension.
* **Serious:** Hypokalemia, hyponatremia, hypomagnesemia, hypocalcemia, hyperuricemia (gout risk), hyperglycemia, ototoxicity (dose-related), and dehydration.
## Key Drug Interactions
* **Aminoglycosides:** Increased risk of ototoxicity and nephrotoxicity.
* **Lithium:** Furosemide may reduce renal clearance of lithium, increasing toxicity risk.
* **NSAIDs:** May reduce the diuretic, natriuretic, and antihypertensive effects of furosemide.
* **ACE Inhibitors/ARBs:** Increased risk of profound hypotension and acute kidney injury, especially when initiating therapy.
## Monitoring
* Serum electrolytes (potassium, sodium, magnesium, calcium).
* Renal function (BUN, creatinine).
* Blood pressure and fluid status (daily weight, input/output).
* Blood glucose and uric acid in patients at risk.
* Monitor for signs of ototoxicity (tinnitus, hearing loss).
## Clinical Pearls
* **Diuretic Resistance:** If response is inadequate at high oral doses, consider switching to twice-daily dosing or IV administration (IV:PO ratio is generally 1:2).
* **Timing:** Administer in the morning to prevent nocturia.
* **Potassium Supplementation:** Prophylactic potassium supplementation is frequently required to prevent hypokalemia.
* **Photosensitivity:** Patients may experience increased sensitivity to sunlight.
* **Availability:** Generic furosemide is widely available; however, bioequivalence between brands can vary; maintain consistent formulation where possible in clinically stable patients.
***
*Disclaimer: This information is for educational purposes only. Clinical practice guidelines change Frequently. Always verify specific dosing, safety profiles, and institutional protocols with current prescribing information, official labeling, and pharmacy databases before administering any medication.*
