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Furosemide (Monograph)

Brand name: Lasix
Drug class: Loop Diuretics
- Loop Diuretics
- Diuretics, Loop

Medically reviewed by on Apr 10, 2024. Written by ASHP.


A standardized concentration for this drug has been established through Standardize 4 Safety (S4S), a national patient safety initiative to reduce medication errors, especially during transitions of care. The drug is included in a standard concentration list which may apply to an IV or oral compounded liquid formulation. For additional information, see the ASHP website [Web].


  • Furosemide is a potent diuretic that given in excessive amounts may induce a profound diuresis with water and electrolyte depletion. Careful medical supervision is required; dosage selection and titration should be adjusted to the individual patient’s needs. (See Dosage and Administration.)


A sulfonamide, loop-type diuretic and antihypertensive agent.

Uses for Furosemide


Management of edema associated with heart failure, hepatic cirrhosis, and renal disease (e.g., nephrotic syndrome).

Considered a diuretic of choice for most patients with heart failure.

Most experts state that all patients with symptomatic heart failure who have evidence for, or a history of, fluid retention generally should receive diuretic therapy in conjunction with moderate sodium restriction, an agent to inhibit the renin-angiotensin-aldosterone (RAA) system (e.g., ACE inhibitor, angiotensin II receptor antagonist, angiotensin receptor-neprilysin inhibitor [ARNI]), a β-adrenergic blocking agent (β-blocker), and in selected patients, an aldosterone antagonist.

IV management of acute pulmonary edema (in combination with oxygen and a cardiac glycoside).


Management of hypertension, alone or in combination with other classes of antihypertensive agents.

Not considered a preferred agent for initial management of hypertension according to current evidence-based hypertension guidelines; other agents (i.e., ACE inhibitors, angiotensin II receptor antagonists, calcium-channel blockers, thiazide diuretics) are preferred for initial management.

Some experts state that loop diuretics (e.g., bumetanide, furosemide, torsemide) are preferred over thiazides in patients with moderate to severe chronic kidney disease (CKD) or symptomatic heart failure.

Individualize choice of therapy; consider patient characteristics (e.g., age, ethnicity/race, comorbidities, cardiovascular risk) as well as drug-related factors (e.g., ease of administration, availability, adverse effects, cost).

A 2017 ACC/AHA multidisciplinary hypertension guideline classifies BP in adults into 4 categories: normal, elevated, stage 1 hypertension, and stage 2 hypertension. (See Table 1.)

Source: Whelton PK, Carey RM, Aronow WS et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018;71:e13-115.

Individuals with SBP and DBP in 2 different categories (e.g., elevated SBP and normal DBP) should be designated as being in the higher BP category (i.e., elevated BP).

Table 1. ACC/AHA BP Classification in Adults1200


SBP (mm Hg)

DBP (mm Hg)









Hypertension, Stage 1




Hypertension, Stage 2




The goal of hypertension management and prevention is to achieve and maintain optimal control of BP. However, the BP thresholds used to define hypertension, the optimum BP threshold at which to initiate antihypertensive drug therapy, and the ideal target BP values remain controversial.

The 2017 ACC/AHA hypertension guideline generally recommends a target BP goal (i.e., BP to achieve with drug therapy and/or nonpharmacologic intervention) of <130/80 mm Hg in all adults regardless of comorbidities or level of atherosclerotic cardiovascular disease (ASCVD) risk. In addition, an SBP goal of <130 mm Hg generally is recommended for noninstitutionalized ambulatory patients ≥65 years of age with an average SBP of ≥130 mm Hg. These BP goals are based upon clinical studies demonstrating continuing reduction of cardiovascular risk at progressively lower levels of SBP.

Other hypertension guidelines generally have based target BP goals on age and comorbidities. Guidelines such as those issued by the JNC 8 expert panel generally have targeted a BP goal of <140/90 mm Hg regardless of cardiovascular risk, and have used higher BP thresholds and target BPs in elderly patients compared with those recommended by the 2017 ACC/AHA hypertension guideline.

Some clinicians continue to support previous target BPs such as those recommended by JNC 8 due to concerns about the lack of generalizability of data from some clinical trials (e.g., SPRINT study) used to support the 2017 ACC/AHA hypertension guideline and potential harms (e.g., adverse drug effects, costs of therapy) versus benefits of BP lowering in patients at lower risk of cardiovascular disease.

Consider potential benefits of hypertension management and drug cost, adverse effects, and risks associated with the use of multiple antihypertensive drugs when deciding a patient's BP treatment goal.

For decisions regarding when to initiate drug therapy (BP threshold), the 2017 ACC/AHA hypertension guideline incorporates underlying cardiovascular risk factors. ASCVD risk assessment is recommended by ACC/AHA for all adults with hypertension.

ACC/AHA currently recommend initiation of antihypertensive drug therapy in addition to lifestyle/behavioral modifications at an SBP ≥140 mm Hg or DBP ≥90 mm Hg in adults who have no history of cardiovascular disease (i.e., primary prevention) and a low ASCVD risk (10-year risk <10%).

For secondary prevention in adults with known cardiovascular disease or for primary prevention in those at higher risk for ASCVD (10-year risk ≥10%), ACC/AHA recommend initiation of antihypertensive drug therapy at an average SBP ≥130 mm Hg or an average DBP ≥80 mm Hg.

Adults with hypertension and diabetes mellitus, CKD, or age ≥65 years are assumed to be at high risk for cardiovascular disease; ACC/AHA state that such patients should have antihypertensive drug therapy initiated at a BP ≥130/80 mm Hg. Individualize drug therapy in patients with hypertension and underlying cardiovascular or other risk factors.

In stage 1 hypertension, experts state that it is reasonable to initiate drug therapy using the stepped-care approach in which one drug is initiated and titrated and other drugs are added sequentially to achieve the target BP. Initiation of antihypertensive therapy with 2 first-line agents from different pharmacologic classes recommended in adults with stage 2 hypertension and average BP >20/10 mm Hg above BP goal.

Furosemide Dosage and Administration



Monitoring and BP Treatment Goals


Administer orally, IV, or IM.

Oral Administration

Administer orally once (preferably in the morning) or twice daily .

For ease of administration and maximum dosage flexibility in children, consider use of oral solution preparation.

IV Administration

For solution and drug compatibility information, see Compatibility under Stability.

IV administration may be used in emergency clinical circumstances when a rapid onset of diuresis is desired, or in patients unable to take oral medication or those with impaired GI absorption; replace with oral therapy as soon as possible.

Consider the potential risks, when using large parenteral doses; monitor patient closely.


For IV infusion, dilute in 5% dextrose, 0.9% sodium chloride, or lactated Ringer’s injection and adjust pH to >5.5.

Rate of Administration

For direct IV injection, administer slowly over a period of 1–2 minutes.

If high-dose parenteral furosemide therapy is necessary, the manufacturer recommends that the drug be administered as a controlled infusion at a rate not exceeding 4 mg/minute in adults.


Individualize dosage according to patient’s requirements and response; titrate dosage to gain maximum therapeutic effect while using the lowest possible effective dosage. (See Boxed Warning.)

Pediatric Patients


2 mg/kg administered as a single dose. If necessary, increase in increments of 1 or 2 mg/kg every 6–8 hours to a maximum of 6 mg/kg. Generally not necessary to exceed individual doses of 4 mg/kg or a dosing frequency of once or twice daily. Use minimum effective dosage for maintenance therapy.

IV or IM

1 mg/kg administered as a single IM or IV injection. If necessary for resistant forms of edema, the initial dose may be increased by 1 mg/kg no more often than every 2 hours until the desired effect has been obtained or up to a maximum dosage of 6 mg/kg. Adequate response usually is obtained with individual parenteral doses of 1 mg/kg.

Acute Pulmonary Edema
IV or IM

1 mg/kg administered as a single IM or IV injection. If necessary for resistant forms of edema, the initial dose may be increased by 1 mg/kg no more often than every 2 hours until the desired effect has been obtained or up to a maximum dosage of 6 mg/kg. Adequate response generally obtained with 1 mg/kg.

Hypertension† [off-label]

Initially, 0.5–2 mg/kg given once or twice daily. Increase as necessary up to a maximum of 6 mg/kg daily.



20–80 mg given as a single dose, preferably in the morning. If needed, repeat same dose 6–8 hours later or increase dose by 20- to 40-mg increments and give no sooner than 6–8 hours after last dose until desired diuretic response (including weight loss) is obtained. May titrate carefully up to 600 mg daily in severe cases.

The effective dose may be given once or twice daily thereafter, or, in some cases, by intermittent administration on 2–4 consecutive days each week. Dosage may be reduced for maintenance therapy.

For management of fluid retention (e.g., edema) associated with heart failure, some experts recommend initiating furosemide at a low dosage (e.g., 20–40 mg once or twice daily) and increasing dosage (maximum 600 mg daily) until urine output increases and weight decreases, generally by 0.5–1 kg daily.

IV or IM

20–40 mg given as a single IM or IV injection. If needed, repeat same dose 2 hours later or increase dose by 20-mg increments and give no sooner than every 2 hours until the desired diuretic response is obtained. Effective dosages may then be given once or twice daily.

Acute Pulmonary Edema

40 mg given as a single IV injection. If needed, an 80-mg dose may be given 1 hour after the initial dose.


40 mg twice daily. If desired BP not attained, consider adding other antihypertensive agents.

Some experts state that usual dosage range is 20–80 mg daily in 2 divided doses.

Prescribing Limits

Pediatric Patients


Maximum of 6 mg/kg.

IV or IM

Maximum of 6 mg/kg in infants and children; do not exceed 1 mg/kg daily in premature infants.

Hypertension† [off-label]

Maximum 6 mg/kg daily.



Maximum of 600 mg daily.

Special Populations

Renal Impairment

Higher doses may be required for patients with acute or chronic renal failure.

Cautions for Furosemide




Hepatic Effects

Sudden alterations of electrolyte balance in patients with cirrhosis may precipitate hepatic coma; use with caution in patients with hepatic cirrhosis and ascites.

Do not initiate therapy in patients with hepatic coma or electrolyte depletion until the basic condition is improved. Therapy in such patients is best initiated in the hospital with careful monitoring of clinical status and electrolyte balance.

Renal Effects

If increasing azotemia and oliguria occur during treatment of severe progressive renal disease, discontinue the drug.

Sensitivity Reactions


Anaphylaxis (e.g., urticaria, angioedema, hypotension) within 5 minutes after IV administration reported.

Systemic Lupus Erythematosus

Possible exacerbation or activation of systemic lupus erythematosus.

Sulfonamide Sensitivity

Patients sensitive to sulfonamides may show allergic reactions to furosemide.


Photosensitivity may occur.

Major Toxicities


Risk of tinnitus, reversible or permanent hearing impairment increased following IV or IM administration, especially at high dosages, after too-rapid administration, in patients with severely impaired renal function, and/or in patients receiving other ototoxic drugs (e.g., aminoglycosides). (See Specific Drugs under Interactions.)

If high-dose IV therapy is indicated, administer by slow IV infusion (e.g., at a rate not exceeding 4 mg/minute in adults).

General Precautions

Fluid, Electrolyte, and Cardiovascular Effects

Excessive diuresis may cause dehydration and blood volume reduction with circulatory collapse and possibly vascular thrombosis and embolism, particularly in elderly patients. (See Boxed Warning.)

Risk of orthostatic hypotension, especially with brisk diuresis. May be aggravated by concomitant use with alcohol, barbiturates, or narcotics.

Risk of hypokalemia, especially with brisk diuresis, inadequate oral electrolyte intake, when cirrhosis is present, or during concomitant use of corticosteroids or ACTH. Concomitant therapy with digitalis may exaggerate metabolic effects of hypokalemia, especially myocardial effects.

Observe carefully for manifestations of fluid and electrolyte depletion (e.g., dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, arrhythmia, nausea, vomiting).

Endocrine Effects

Possible increased blood glucose and alterations in glucose tolerance tests (with abnormalities of the fasting and 2-hour postprandial sugar); precipitation of diabetes mellitus rarely reported. Monitor urine and blood glucose concentrations periodically in patients with diabetes and those suspected of latent diabetes.

Possible hyperuricemia and precipitation of gout; use with caution in patients with a history of gout or elevated serum uric acid concentrations.

Patient Monitoring

Monitor regularly for the possible occurrence of blood dyscrasias, liver or kidney damage, or other idiosyncratic reactions.

Serum electrolytes (particularly potassium), CO2, Scr, and BUN should be determined frequently during the first few months of therapy and periodically thereafter.

Elective Surgery

Discontinue therapy 1 week (oral furosemide) or 2 days (parenteral furosemide) before elective surgery.

Specific Populations


Category C.


Distributed into milk. Use with caution.

Pediatric Use

Risk of persistent patent ductus arteriosus (PDA) may be increased in premature neonates with respiratory distress syndrome (RDS) who receive furosemide during the first weeks of life.

Do not exceed dosage of 1 mg/kg per 24 hours in premature neonates with <31 weeks’ postconception age (gestational age at birth plus postnatal age); risk of potentially toxic furosemide plasma concentrations with higher dosages.

Renal calcification reported in severely premature infants treated with IV furosemide for edema due to PDA and hyaline membrane disease; concomitant chlorothiazide therapy may decrease hypercalciuria and dissolve some calculi.

Hearing loss reported in neonates; possibly secondary to renal immaturity.

Oral solutions contain sorbitol; high dosages may cause diarrhea in children.

Hepatic Impairment

Use with caution.

Renal Impairment

Use with caution.

Common Adverse Effects

Orthostatic hypotension, dizziness, electrolyte imbalance (hyponatremia, hypokalemia, hypochloremia) tinnitus, photosensitivity.

Drug Interactions

Specific Drugs





May aggravate orthostatic hypotension

Anticonvulsants (e.g., phenytoin sodium, phenobarbital)

Possible reduced diuretic effect

Antidiabetic agents (e.g., insulin, oral agents)

Possible antagonism of hypoglycemic effect as result of hypokalemia

Observe for possible decreased diabetic control; correct potassium deficit and/or adjust dosage of antidiabetic agent

Antihypertensive agents

Additive antihypertensive effect; orthostatic hypotension may occur

Reduce dosage of both drugs

Concomitant therapy generally used to therapeutic advantage


May aggravate orthostatic hypotension

Cardiac glycosides (e.g., digoxin)

Possible electrolyte disturbances (e.g., hypokalemia, hypomagnesemia), increased risk of digitalis toxicity, and/or fatal cardiac arrhythmias

Monitor electrolytes; correct hypokalemia

Chloral hydrate (no longer commercially available in the US)

Possible reaction characterized by diaphoresis, flushes, hypertension, and uneasiness in patients with acute MI and heart failure

Consider alternate hypnotic drug (e.g., a benzodiazepine) in patients who require IV furosemide

Diuretics, loop (e.g., bumetanide, ethacrynic acid, torsemide)

Share similar diuretic mechanisms

No therapeutic rationale for concomitant use

Diuretics, potassium- sparing (e.g., amiloride, spironolactone, triamterene)

Possible reduction in potassium loss

May be used to therapeutic advantage

Diuretics, thiazides

Additive diuretic effect

Use reduced dosage of furosemide when added to existing diuretic regimen

Drugs that cause potassium loss (e.g., corticosteroids, corticotropin, amphotericin B)

Additive hypokalemic effects

Monitor electrolytes; correct hypokalemia


Possible decreased diuretic and natriuretic effect

Monitor closely to determine if desired diuretic and/or hypotensive effect is obtained


Reduced renal clearance of lithium and increased risk of lithium toxicity

Avoid concomitant use; if concomitant therapy is necessary, monitor for lithium toxicity


May aggravate orthostatic hypotension

Neuromuscular blocking agents, nondepolarizing (e.g., atracurium besylate, tubocurarine chloride)

Potential for prolonged neuromuscular blockade


Decreased arterial responsive to norepinephrine

Norepinephrine may still be used effectively


Possible weight gain and increased Scr, serum potassium concentrations, and BUN (NSAIAs)

Ototoxic drugs (e.g., aminoglycoside antibiotics)

Possible additive ototoxic effect, especially in patients with impaired renal function

Avoid concomitant use except in life-threatening situations

Salicylates (e.g., aspirin)

Possible transient reductions in Clcr in patient with chronic renal insufficiency

Monitor for toxicity


May potentiate action of succinylcholine


Possible reduced natriuretic and antihypertensive effects

Do not administer simultaneously; separate administration by ≥2 hours

Observe closely for desired diuretic and/or antihypertensive effect

Uricosuric drugs (probenecid, sulfinpyrazone)

Possible antagonism of uricosuric effects

Monitor serum uric acid concentrations

Furosemide Pharmacokinetics



Mean oral bioavailability of furosemide from commercially available tablets and oral solution is 64% and 60%, respectively.

Commercially available tablets and oral solution are bioequivalent.


Following oral administration, onset of diuresis occurs within 30 minutes to 1 hour; maximal effect after 1–2 hours.

Following IV administration, diuresis occurs within 5 minutes and peaks within 20–60 minutes.

Onset of diuresis after IM administration occurs somewhat later than after IV administration.

Maximum hypotensive effect may not be apparent until after several days of therapy.


Diuretic effect persists 6–8 hours following oral administration and approximately 2 hours following IV administration.


Food does not appear to affect diuretic effect.

Special Populations

In patients with severely impaired renal function, the diuretic response may be prolonged.



Crosses the placenta and is distributed into milk.

Plasma Protein Binding

Approximately 95% bound to plasma proteins (mainly albumin) in both normal and azotemic patients.



Metabolized in the liver to the defurfurylated derivative, 4-chloro-5-sulfamoylanthranilic acid.

Elimination Route

Rapidly excreted in urine by glomerular filtration and by secretion from the proximal tubule.

Approximately 50% of an oral dose and 80% of an IV or IM dose are excreted in urine within 24 hours; 69–97% of these amounts is excreted in the first 4 hours. The remainder of the drug is eliminated by nonrenal mechanisms including degradation in the liver and excretion of unchanged drug in the feces.


Biphasic; terminal half-life is approximately 2 hours.

Special Populations

Hepatic or renal impairment prolongs the elimination half-life of the drug.

In patients with marked renal impairment without liver disease, nonrenal clearance is increased to the extent that up to 98% of the drug is cleared within 24 hours.

Not removed by hemodialysis.




Solution or Tablets

Tight, light resistant containers at 15–30°C.



15–30°C; protect from light. Discard unused portion.



Do not mix with strongly acidic solutions (i.e., pH < 5.5), such as those containing ascorbic acid, amrinone, ciprofloxacin, labetalol, tetracycline, milrinone, epinephrine, or norepinephrine, because furosemide may be precipitated.

Solution Compatibilitya


Alcohol 5% and dextrose 5%

Amino acids 4.25%, dextrose 25%

Dextrose 5% in Ringer’s injection, lactated

Dextrose 5% in sodium chloride 0.9%

Dextrose 5, 10, or 20% in water

Invert sugar 10% in Electrolyte #1

Mannitol 20%

Ringer’s injection, lactated

Sodium chloride 0.9%

Sodium lactate (1/6) M


Fructose 10% in water

Invert sugar 10% in Electrolyte #2

Drug Compatibility
Admixture Compatibilitya


Amikacin sulfate


Ampicillin sodium

Atropine sulfate


Calcium gluconate

Cefuroxime sodium

Cimetidine HCl

Dexamethasone sodium phosphate

Diamorphine HCl


Epinephrine HCl

Heparin sodium

Hydrocortisone sodium succinate

Isosorbide dinitrate

Kanamycin sulfate

Lidocaine HCl

Midazolam HCl


Morphine sulfate


Penicillin G

Potassium chloride

Ranitidine HCl

Scopolamine butylbromide

Sodium bicarbonate



Tobramycin sulfate


Buprenorphine HCl

Chlorpromazine HCl


Dobutamine HCl

Erythromycin lactobionate

Isoproterenol HCl

Meperidine HCl

Metoclopramide HCl


Prochlorperazine edisylate

Promethazine HCl


Amiodarone HCl

Gentamicin sulfate

Hydrocortisone sodium succinate

Verapamil HCl

Y-Site Compatibilitya


Allopurinol sodium


Amikacin sulfate

Amphotericin B cholesteryl sulfate complex



Bleomycin sulfate

Cefepime HCl






Dexmedetomidine HCl


Doxorubicin HCl liposome injection

Epinephrine HCl

Etoposide phosphate

Fentanyl citrate

Fludarabine phosphate


Foscarnet sodium

Granisetron HCl

Heparin sodium

Hetastarch in lactated electrolyte injection (Hextend)

Hydrocortisone sodium succinate

Hydromorphone HCl

Indomethacin sodium trihydrate

Kanamycin sulfate

Leucovorin calcium



Melphalan HCl


Methotrexate sodium



Norepinephrine bitartrate


Piperacillin sodium–tazobactam sodium

Potassium chloride


Ranitidine HCl

Remifentanil HCl


Sodium nitroprusside


Tirofiban HCl




Tobramycin sulfate

Vitamin B complex with C




Chlorpromazine HCl



Diltiazem HCl


Esmolol HCl

Fenoldopam mesylate




Gemcitabine HCl

Gentamicin sulfate

Hydralazine HCl

Idarubicin HCl


Metoclopramide HCl

Midazolam HCl

Milrinone lactate

Nicardipine HCl

Ondansetron HCl

Quinidine gluconate

Thiopental sodium

Vecuronium bromide

Vinblastine sulfate

Vincristine sulfate

Vinorelbine tartrate


Amiodarone HCl

Dobutamine HCl

Dopamine HCl

Doxorubicin HCl


Labetalol HCl

Meperidine HCl

Morphine sulfate


Advice to Patients

Additional Information

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer’s labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name



Dosage Forms


Brand Names




40 mg/5 mL*

Furosemide Solution

10 mg/mL*

Furosemide Solution


20 mg*

Furosemide Tablets



40 mg*

Furosemide Tablets

Lasix (scored)


80 mg*

Furosemide Tablets





10 mg/mL*

Furosemide Injection

AHFS DI Essentials™. © Copyright 2024, Selected Revisions April 10, 2024. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Off-label: Use is not currently included in the labeling approved by the US Food and Drug Administration.

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