Furosemide
General
- Type: Diuretic
- Dosage Forms:20, 40, 80
- Common Trade Names: Lasix
- Approximately 50% bioavailability, so converting from oral to IV dose doubles oral dose[1]
- Furosemide absorption may be reduced in decompensated CHF[2]
Adult Dosing
40 mg furosemide = 20 mg torsemide = 1 mg bumetanide = 50 mg ethacrynic acid
- Fluid overload: Typically 40 mg IV or normal PO dosage IV
- hypertension: 10-40 mg PO QDAY-BID, max 600 mg/day
- Hypercalcemia: 120 mg/day PO divided QDAY - TID
- Continuous infusion may increase diuresis effect and minimize post-diuretic sodium retention and "diuretic braking"[3]
- Start 0.1 mg/kg/hr, increase hourly to max of 0.75 mg/kg/hr[4]
- Target > 1 mL/kg/hr
- Monitor for ototoxicity
Pediatric Dosing
- Volume overload 0.5-2mg/kg/dose IV
Special Populations
- Pregnancy Rating:C
- Lactation: safety unknown
- Renal Dosing
- Adult: no adjustment, contraindicated in anuria
- Pediatric: no adjustment, contraindicated in anuria
- Hepatic Dosing
- Adult: not defined
- Pediatric: not defined
Contraindications
- Allergy to class/drug
- anuria
- electrolyte imbalances
Adverse Reactions
Serious
- hypokalemia
- metabolic alkalosis
- hypovolemia
- ototoxicity
- hemolytic anemia
- vasculitis
- steven-johnson syndrome
- pancreatitis
- eosinophilia
Common
- urinary frequency
- dizziness
- nausea/vomiting
- weakness
- muscle cramping
- hypokalemia
- hypomagnesemia
- blurred vision
- diarrhea
- hyperglycemia
- hyperuricemia
- tinnitus
Pharmacology
- Half-life: 30-60 min
- Metabolism: liver minimally
- Excretion: urine
- Mechanism of Action: inhibits loop of henle and proximal and distal convoluted tubule sodium and chloride resorption
Indications by Condition
The following table is automatically generated from disease/condition pages across WikEM.
| Indication | Dose | Context | Route | Population |
|---|---|---|---|---|
| Coarctation of the aorta | 1-2mg/kg IV | CHF management | IV | Pediatric |
| Congestive heart failure | Double home dose IV or up to 2.5x dose (e.g., if 40 mg PO daily → 40-100 mg IV) | Diuresis (hold if no fluid overload; give nitrates first) | IV | Adult |
| Hypermagnesemia | 20-40mg | Promote renal magnesium excretion | IV | Adult |
| Idiopathic intracranial hypertension | 20mg BID | Adjunctive diuresis | PO | Adult |
| Pulmonary edema | 20-40mg | Diuresis after nitroglycerin has been initiated | IV | Adult |
| Volume overload | 20-40mg IV bolus (diuretic-naive); or IV dose >= home oral daily dose | Loop diuretic, first-line for decongestion | IV | Adult |
See Also
References
- ↑ Asare K. Management of Loop Diuretic Resistance in the Intensive Care Unit. Am J Health Syst Pharm. 2009;66(18):1635-1640.
- ↑ Vasko MR, Brown-Cartwright D, Knochel JP et al. Furosemide absorption is altered in decompensated congestive heart failure. Ann Intern Med. 1985; 102: 314–8.
- ↑ Pivac N, Rumboldt Z, Sardelic S et al. Diuretic effects of furosemide infusion versus bolus injection in congestive heart failure. Int J Clin Pharmacol Res. 1998; 18:121–8.
- ↑ Schuller D, Lynch JP, Fine D. Protocol-guided diuretic management: comparison of furosemide by continuous infusion and intermittent bolus. Crit Care Med. 1997; 25:1969–75.