Furosemide: Uses, Side Effects, and How to Take It Safely
Furosemide is a prescription loop diuretic, commonly called a “water pill,” that helps the body remove extra fluid and salt. It is used to treat fluid buildup from conditions such as heart failure, kidney disease, or liver disease, and it may also be used for high blood pressure.
Furosemide can help reduce swelling and manage blood pressure, but it may cause dehydration and changes in electrolytes. Take it only as prescribed and ask your doctor or pharmacist about monitoring and food or medication precautions.
Key facts at a glance
- ATC
- C03CA01
- Generic
- Furosemide
- Class
- loop-diuretic
- Brands
- Lasix
- Availability
- rx
- Pregnancy
- C
- Lactation
- unsafe
- Half-life (h)
- 2
- Onset (min)
- 30
- Duration (h)
- 6
- Routes
- oral, iv
- Forms
- tablet, injection
- Regions
- CN, US, EU, JP
- Monitoring
- electrolytes, renal-function, blood-pressure
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
10 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring
Use with caution and monitor for adverse effects.
pregnancy
third trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring, monitor amniotic fluid levels
Use with caution and monitor for adverse effects.
lactation
breastfeedinguse with caution
furosemide passes into breast milk in small amounts, monitor infant for dehydration or electrolyte disturbances
monitor infant for adequate hydration and weight gain
Use with caution and monitor for adverse effects.
pediatric_age
neonatesuse with extreme caution, weight-based dosing
use only in hospital setting with close monitoring, typical dose 1-2 mg/kg
monitor electrolytes, renal function, fluid status closely
Use with caution and monitor for adverse effects.
pediatric_age
childrenweight-based dosing required
initiate at 1-2 mg/kg once or twice daily, maximum 6 mg/kg per day
monitor electrolytes, renal function, and fluid status regularly
geriatric
elderlystart with lower dose
start at 20-40 mg daily, titrate slowly, monitor blood pressure and renal function
monitor electrolytes, renal function, blood pressure, and for signs of dehydration
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderatemay need higher doses for diuretic effect
may require higher doses for adequate diuretic response, divide doses if needed
monitor renal function, electrolytes, and diuretic response
Use with caution and monitor for adverse effects.
renal_impairment
severesignificant dose adjustment required
use cautiously, may need higher or more frequent dosing, consider continuous infusion
close monitoring of renal function, electrolytes, and audiometric testing
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateno significant adjustment needed initially
use standard dosing initially, monitor electrolytes closely
monitor electrolytes, especially potassium and magnesium
Use with caution and monitor for adverse effects.
hepatic_impairment
severemay need dose reduction
use cautiously in severe hepatic impairment, may need dose reduction, avoid rapid diuresis
close monitoring of electrolytes, mental status for encephalopathy
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
Year FDA approved Furosemide for medical use
Drug class
Pharmacological classification of Furosemide
Common uses
Primary therapeutic indications
Mechanism of action
Pharmacological mechanism
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 22, 2026. · Read our editorial policy