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Furosemide

Medically reviewed by Drugs.com. Last updated on Apr 27, 2020.

Pronunciation

(fyoor OH se mide)

Index Terms

  • Frusemide

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Injection:

Generic: 10 mg/mL (2 mL, 4 mL, 10 mL)

Solution, Injection [preservative free]:

Generic: 10 mg/mL (2 mL, 4 mL, 10 mL)

Solution, Oral:

Generic: 8 mg/mL (500 mL); 10 mg/mL (60 mL, 120 mL)

Tablet, Oral:

Lasix: 20 mg

Lasix: 40 mg, 80 mg [scored]

Generic: 20 mg, 40 mg, 80 mg

Brand Names: U.S.

  • Lasix

Pharmacologic Category

  • Antihypertensive
  • Diuretic, Loop

Pharmacology

Primarily inhibits reabsorption of sodium and chloride in the ascending loop of Henle and proximal and distal renal tubules, interfering with the chloride-binding cotransport system, thus causing its natriuretic effect (Rose 1991).

Metabolism

Minimally hepatic

Excretion

Urine (Oral: 50%, IV: 80%) within 24 hours; feces (as unchanged drug); nonrenal clearance prolonged with renal impairment

Onset of Action

Diuresis: Oral, sublingual: 30 to 60 minutes.

Symptomatic improvement with acute pulmonary edema: Within 15 to 20 minutes; occurs prior to diuretic effect.

Peak effect: Oral, SL: 1 to 2 hours; IV: 0.5 hours.

Duration of Action

Oral, sublingual: 6 to 8 hours; IV: 2 hours

Half-Life Elimination

Normal renal function: 0.5 to 2 hours; End-stage renal disease (ESRD): 9 hours

Protein Binding

91% to 99%; primarily to albumin

Use: Labeled Indications

Edema: Management of edema associated with heart failure, cirrhosis of the liver (ie, ascites), or renal disease (including nephrotic syndrome); acute pulmonary edema.

Contraindications

Hypersensitivity to furosemide or any component of the formulation; anuria

Canadian labeling: Additional contraindications (not in US labeling): Hypersensitivity to sulfonamide-derived drugs; complete renal shutdown; hepatic coma and precoma; uncorrected states of electrolyte depletion, hypovolemia, dehydration, or hypotension; jaundiced newborn infants or infants with disease(s) capable of causing hyperbilirubinemia and possibly kernicterus; breast-feeding. Note: Manufacturer labeling for Lasix Special and Furosemide Special Injection also includes: GFR <5 mL/minute or GFR >20 mL/minute; hepatic cirrhosis; renal failure accompanied by hepatic coma and precoma; renal failure due to poisoning with nephrotoxic or hepatotoxic substances.

Note: Although the approved product labeling states this medication is contraindicated with other sulfonamide-containing drug classes, the scientific basis of this statement has been challenged. See “Warnings/Precautions” for more detail.

Dosing: Adult

Note: Loop diuretic approximate oral dose equivalency for patients with normal renal function: Furosemide 40 mg = bumetanide 1 mg = torsemide 20 mg (ACCF/AHA [Yancy 2013]; Brater 2019a; Brater 1983; Felker 2011). Some experts suggest an approximate oral dose equivalency of furosemide 40 mg = bumetanide 1 mg = torsemide 10 mg (Felker 2012; Vargo 1995).

Ascites, due to cirrhosis:

Note: Generally used in combination with spironolactone but may be used as monotherapy for patients with hyperkalemia. For combination therapy, a dosing ratio of spironolactone 100 mg to furosemide 40 mg should generally be maintained but can be adjusted for electrolyte abnormalities (AASLD [Runyon 2013]; Runyon 2020).

Oral: Initial: 40 mg once daily; titrate every 3 to 5 days based on response and tolerability; once-daily dosing is preferred; maximum dose: 160 mg once daily (AASLD [Runyon 2013]; Runyon 2020). For small-volume ascites in patients who weigh <50 kg, some experts recommend a starting dose of 20 mg once daily (Runyon 2020).

Edema (eg, peripheral, pulmonary, generalized):

Naive to loop diuretics:

Oral, IV: Initial: 20 to 40 mg once then titrate as needed to an effective dose (see Titration to effect below) (Brater 2011; Sterns 2019).

Note: Oral bioavailability varies widely but on average is 50% of the IV dose (Brater 2011).

Refractory edema or acute decompensation in patients taking oral loop diuretics:

IV: Bolus/intermittent dosing: Initial: Administer 1 to 2.5 times the total daily oral maintenance dose once (eg, a patient taking oral furosemide 40 mg twice daily at home [80 mg/day] can be given 80 mg to 200 mg IV as an initial bolus) then titrate as needed to an effective dose (see Titration to effect below) (ACC [Hollenberg 2019]; Brater 2011; Brater 2020; Colucci 2019; Felker 2011).

Continuous infusion: Note: Reserve for patients who have responded to bolus therapy.

eGFR ≥30 mL/minute/1.73 m2: IV: Initial: 5 mg/hour; if diuretic response is not adequate, repeat IV bolus dose and increase continuous infusion to 10 mg/hour; continue to bolus and titrate infusion as needed up to 40 mg/hour (Brater 2011; Brater 2020).

eGFR <30 mL/minute/1.73 m2: IV: Initial: 20 mg/hour; if diuretic response is not adequate, repeat IV bolus dose and increase continuous infusion to 40 mg/hour (Brater 2011; Brater 2020).

Note: Higher continuous infusion rates have been described but are not recommended due to potential for side effects; consider alternative strategies for fluid removal (Brater 2020).

Titration to effect: If the initial dose does not result in diuresis, double the individual dose (rather than administer the same dose more frequently) until diuresis occurs. Titration of an IV dose can occur at ≥2-hour intervals as needed in hospitalized patients. Once an effective dose is identified, it is typically administered once or twice daily but may be given more frequently if needed. The maximum effective dose varies by population; higher-than-usual doses may be required for patients with nephrotic syndrome or renal failure. The maximum recommended total daily dose is 600 mg/day to avoid toxicity (Brater 2011; Brater 2019a; Brater 2020; ACC [Hollenberg 2019]).

Transitioning from IV to oral: There is substantial variability in oral bioavailability; some experts recommend giving 1 to 2 times the IV dose orally (eg, total daily IV dose of 80 mg/day should be converted to an oral dose of 80 to 160 mg/day in 1 to 2 divided doses), then monitoring urine output and adjusting oral dose as needed (Brater 2011; Brater 2020; Kaojarern 1982; Murray 1997; Vargo 1995).

Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.

Dosing: Geriatric

Oral, IV: Initial: 20 mg/day; increase slowly to desired response.

Dosing: Pediatric

Note: Oral and parenteral (IV, IM) doses may not be interchangeable; due to differences in bioavailability, oral doses are typically higher than IV. Oral solution is available in multiple concentrations (8 mg/mL and 10 mg/mL); extra precautions should be taken to verify and avoid confusion between the different concentrations; dose should be clearly presented as mg (not mL). Oral dose equivalency for adult patients with normal renal function (approximate): Furosemide 40 mg = bumetanide 1 mg = torsemide 20 mg = ethacrynic acid 50 mg (Brater 1983; Cody 1994; Vargo 1995).

Edema (diuresis):

Oral: Infants, Children, and Adolescents:

Intermittent dosing (acute): Initial: 2 mg/kg as a single dose; if ineffective, may increase in 6 to 8 hours in increments of 1 to 2 mg/kg/dose; maximum dose: 6 mg/kg/dose.

Maintenance dosing (chronic): Limited data available: Initial: 0.5 to 2 mg/kg/dose every 6 to 24 hours; usual initial adult dose: 20 to 80 mg/dose; if initial dose ineffective, may increase dose in increments of 1 to 2 mg/kg/dose; maximum daily dose: 6 mg/kg/day not to exceed maximum adult daily dose: 600 mg/day; adjust dose to minimal effective dose for maintenance (Flynn 2011; Kliegman 2016; NHBPEP 2004; van der Vorst 2006). Note: Smaller doses on a mg/kg basis may be needed in larger children, especially in those who are diuretic naive.

IM, intermittent IV: Infants, Children, and Adolescents: Limited data available: Initial: 0.5 to 2 mg/kg/dose every 6 to 12 hours; usual initial adult dose: 20 to 40 mg/dose; if initial dose ineffective after 2 hours, may increase dose by 1 mg/kg/dose; maximum dose: 6 mg/kg/dose not to exceed maximum adult dose: 200 mg/dose; adjust to minimal effective dose for maintenance (Brater 1998; Fuhrman 2017; Kliegman 2016; van der Vorst 2006; Wells 1990). Note: Smaller doses on a mg/kg basis may be needed in larger children, especially in those who are diuretic naive. Dosing in adolescents based on experience in adult and pediatric patients.

Continuous IV infusion:

Infants and Children: Limited data available: Initial: IV bolus dose of 0.1 mg/kg followed by continuous IV infusion of 0.05 to 0.4 mg/kg/hour; titrate dosage to clinical effect (Copeland 1983; Luciani 1997; Singh 1992; van der Vorst 2001).

Adolescents: Very limited data available; dosing in adolescents based on reported experience in adult and pediatric patients (ACCF/AHA [Yancy 2013]); Brater 1998; Copeland 1983; Howard 2001; Luciani 1997; Singh 1992; van der Vorst 2001): IV bolus dose of 0.1 mg/kg; usual adult bolus dose: 40 to 100 mg over 1 to 2 minutes; followed by continuous IV infusion of 0.1 to 0.4 mg/kg/hour; usual adult dosing range: 10 to 40 mg/hour.

Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.

Reconstitution

IV infusion solution may be mixed in NS or D5W solution. May also be diluted for infusion to 1 to 2 mg/mL (maximum: 10 mg/mL).

Administration

Parenteral: Undiluted direct IV injections may be administered at a rate of 20 to 40 mg per minute; high doses (eg, ≥160 mg) should be given as a short-term infusion at a maximum rate of administration of 4 mg/minute; exceeding this rate increases the risk of ototoxicity (Brater 2019b).

Oral: May administer with or without food.

Note: When IV or oral administration is not possible, the sublingual route may be used. Place 1 tablet under tongue for at least 5 minutes to allow for maximal absorption. Patients should be advised not to swallow during disintegration time (Haegeli 2007).

Dietary Considerations

May cause potassium loss; potassium supplement or dietary changes may be required.

Storage

Injection: Store at room temperature. Protect from light. Exposure to light may cause discoloration; do not use furosemide solutions if they have a yellow color. Furosemide solutions are unstable in acidic media, but very stable in basic media. Refrigeration may result in precipitation or crystallization; however, resolubilization at room temperature or warming may be performed without affecting the drug's stability. Infusion solution in D5W, NS, or LR is stable for 24 hours at room temperature.

Tablet, solution: Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 89°F). Protect from light. Discard opened bottle of solution after 90 days (10 mg/mL concentration only).

Drug Interactions

Acebrophylline: May enhance the therapeutic effect of Furosemide. Monitor therapy

Ajmaline: Sulfonamides may enhance the adverse/toxic effect of Ajmaline. Specifically, the risk for cholestasis may be increased. Monitor therapy

Alfuzosin: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Aliskiren: May decrease the serum concentration of Furosemide. Monitor therapy

Allopurinol: Loop Diuretics may enhance the adverse/toxic effect of Allopurinol. Loop Diuretics may increase the serum concentration of Allopurinol. Specifically, Loop Diuretics may increase the concentration of Oxypurinol, an active metabolite of Allopurinol. Monitor therapy

Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When amifostine is used at chemotherapy doses, blood pressure lowering medications should be withheld for 24 hours prior to amifostine administration. If blood pressure lowering therapy cannot be withheld, amifostine should not be administered. Consider therapy modification

Amikacin (Oral Inhalation): Loop Diuretics may enhance the nephrotoxic effect of Amikacin (Oral Inhalation). Loop Diuretics may enhance the ototoxic effect of Amikacin (Oral Inhalation). Monitor therapy

Aminoglycosides: Loop Diuretics may enhance the adverse/toxic effect of Aminoglycosides. Specifically, nephrotoxicity and ototoxicity. Monitor therapy

Amphetamines: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Angiotensin-Converting Enzyme Inhibitors: Loop Diuretics may enhance the hypotensive effect of Angiotensin-Converting Enzyme Inhibitors. Loop Diuretics may enhance the nephrotoxic effect of Angiotensin-Converting Enzyme Inhibitors. Monitor therapy

Antidiabetic Agents: Hyperglycemia-Associated Agents may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy

Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Monitor therapy

Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Benperidol: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Beta2-Agonists: May enhance the hypokalemic effect of Loop Diuretics. Monitor therapy

Bilastine: Loop Diuretics may enhance the QTc-prolonging effect of Bilastine. Monitor therapy

Bile Acid Sequestrants: May decrease the absorption of Loop Diuretics. Monitor therapy

Brigatinib: May diminish the antihypertensive effect of Antihypertensive Agents. Brigatinib may enhance the bradycardic effect of Antihypertensive Agents. Monitor therapy

Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Bromperidol: May diminish the hypotensive effect of Blood Pressure Lowering Agents. Blood Pressure Lowering Agents may enhance the hypotensive effect of Bromperidol. Avoid combination

Cabozantinib: MRP2 Inhibitors may increase the serum concentration of Cabozantinib. Monitor therapy

Canagliflozin: May enhance the hypotensive effect of Loop Diuretics. Monitor therapy

Cardiac Glycosides: Loop Diuretics may enhance the adverse/toxic effect of Cardiac Glycosides. Specifically, cardiac glycoside toxicity may be enhanced by the hypokalemic and hypomagnesemic effect of loop diuretics. Monitor therapy

Cefazedone: May enhance the nephrotoxic effect of Loop Diuretics. Monitor therapy

Cefotiam: Loop Diuretics may enhance the nephrotoxic effect of Cefotiam. Monitor therapy

Cefpirome: Loop Diuretics may enhance the nephrotoxic effect of Cefpirome. Monitor therapy

Ceftizoxime: Loop Diuretics may enhance the nephrotoxic effect of Ceftizoxime. Monitor therapy

Cephalothin: Loop Diuretics may enhance the nephrotoxic effect of Cephalothin. Monitor therapy

Cephradine: May enhance the nephrotoxic effect of Loop Diuretics. Monitor therapy

Chloral Betaine: Furosemide may enhance the adverse/toxic effect of Chloral Betaine. Management: Consider alternatives to this combination when possible; if combined use cannot be avoided, monitor closely for evidence of toxicity. Consider therapy modification

Chloral Hydrate: Furosemide may enhance the adverse/toxic effect of Chloral Hydrate. Avoid combination

CISplatin: Loop Diuretics may enhance the nephrotoxic effect of CISplatin. Loop Diuretics may enhance the ototoxic effect of CISplatin. Monitor therapy

Corticosteroids (Systemic): May enhance the hypokalemic effect of Loop Diuretics. Monitor therapy

CycloSPORINE (Systemic): May enhance the adverse/toxic effect of Loop Diuretics. Monitor therapy

Desmopressin: Loop Diuretics may enhance the hyponatremic effect of Desmopressin. Avoid combination

Dexmethylphenidate: May diminish the therapeutic effect of Antihypertensive Agents. Monitor therapy

Diacerein: May enhance the therapeutic effect of Diuretics. Specifically, the risk for dehydration or hypokalemia may be increased. Monitor therapy

Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Dichlorphenamide: Loop Diuretics may enhance the hypokalemic effect of Dichlorphenamide. Monitor therapy

Dofetilide: Loop Diuretics may enhance the QTc-prolonging effect of Dofetilide. Management: Monitor serum potassium and magnesium more closely when dofetilide is combined with loop diuretics. Electrolyte replacements will likely be required to maintain potassium and magnesium serum concentrations. Consider therapy modification

DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. Monitor therapy

Empagliflozin: May enhance the hypotensive effect of Loop Diuretics. Monitor therapy

Ethacrynic Acid: Furosemide may enhance the ototoxic effect of Ethacrynic Acid. Avoid combination

Fexinidazole [INT]: May enhance the arrhythmogenic effect of Loop Diuretics. Avoid combination

Foscarnet: Loop Diuretics may increase the serum concentration of Foscarnet. Management: When diuretics are indicated during foscarnet treatment, thiazides are recommended over loop diuretics. If patients receive loop diuretics during foscarnet treatment, monitor closely for evidence of foscarnet toxicity. Consider therapy modification

Fosphenytoin: May diminish the diuretic effect of Loop Diuretics. Monitor therapy

Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Herbs (Hypotensive Properties): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. Monitor therapy

Ipragliflozin: May enhance the adverse/toxic effect of Loop Diuretics. Specifically, the risk for intravascular volume depletion may be increased. Monitor therapy

Ivabradine: Loop Diuretics may enhance the arrhythmogenic effect of Ivabradine. Monitor therapy

Levodopa-Containing Products: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa-Containing Products. Monitor therapy

Levosulpiride: Loop Diuretics may enhance the adverse/toxic effect of Levosulpiride. Avoid combination

Licorice: May enhance the hypokalemic effect of Loop Diuretics. Monitor therapy

Lithium: Loop Diuretics may decrease the serum concentration of Lithium. Loop Diuretics may increase the serum concentration of Lithium. Monitor therapy

Lormetazepam: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Mecamylamine: Sulfonamides may enhance the adverse/toxic effect of Mecamylamine. Avoid combination

Methotrexate: May diminish the therapeutic effect of Loop Diuretics. Loop Diuretics may increase the serum concentration of Methotrexate. Methotrexate may increase the serum concentration of Loop Diuretics. Monitor therapy

Methylphenidate: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Naftopidil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Neuromuscular-Blocking Agents: Loop Diuretics may diminish the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Loop Diuretics may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy

Nicergoline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Nitisinone: May increase the serum concentration of OAT1/3 Substrates. Monitor therapy

Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents: May diminish the diuretic effect of Loop Diuretics. Loop Diuretics may enhance the nephrotoxic effect of Nonsteroidal Anti-Inflammatory Agents. Management: Monitor for evidence of kidney injury or decreased therapeutic effects of loop diuretics with concurrent use of an NSAID. Consider avoiding concurrent use in CHF or cirrhosis. Concomitant use of bumetanide with indomethacin is not recommended. Consider therapy modification

Nonsteroidal Anti-Inflammatory Agents (Topical): May diminish the therapeutic effect of Loop Diuretics. Monitor therapy

Obinutuzumab: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Consider therapy modification

Opioid Agonists: May enhance the adverse/toxic effect of Diuretics. Opioid Agonists may diminish the therapeutic effect of Diuretics. Monitor therapy

Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Phenytoin: May diminish the diuretic effect of Loop Diuretics. Monitor therapy

Pholcodine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Pholcodine. Monitor therapy

Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Pretomanid: May increase the serum concentration of OAT1/3 Substrates. Monitor therapy

Probenecid: May enhance the adverse/toxic effect of Loop Diuretics. Probenecid may diminish the diuretic effect of Loop Diuretics. Probenecid may increase the serum concentration of Loop Diuretics. Management: Monitor for decreased diuretic effects or increased adverse effects of loop diuretics with concomitant use of probenecid. Bumetanide prescribing information recommends against concomitant use of probenecid. Monitor therapy

Promazine: Loop Diuretics may enhance the QTc-prolonging effect of Promazine. Avoid combination

Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Monitor therapy

Reboxetine: May enhance the hypokalemic effect of Loop Diuretics. Monitor therapy

RisperiDONE: Loop Diuretics may enhance the adverse/toxic effect of RisperiDONE. Monitor therapy

Salicylates: May diminish the diuretic effect of Loop Diuretics. Loop Diuretics may increase the serum concentration of Salicylates. Monitor therapy

Sodium Phosphates: Diuretics may enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with diuretics, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, hydrate adequately and monitor fluid and renal status. Consider therapy modification

Sucralfate: May decrease the serum concentration of Furosemide. Sucralfate may impair the absorption of furosemide. Management: Avoid concomitant oral administration of furosemide and sucralfate. Separate administration by at least 2 hours. Does not apply to parenterally administered furosemide. Consider therapy modification

Teriflunomide: May increase the serum concentration of OAT1/3 Substrates. Monitor therapy

Thyroid Products: Furosemide may decrease the protein binding of Thyroid Products. This may lead to a transient increase in free thyroid hormone concentrations and to a later decrease in total thyroid hormone concentrations. Monitor therapy

Tobramycin (Oral Inhalation): Loop Diuretics may enhance the nephrotoxic effect of Tobramycin (Oral Inhalation). Loop Diuretics may enhance the ototoxic effect of Tobramycin (Oral Inhalation). Monitor therapy

Tolvaptan: May increase the serum concentration of OAT1/3 Substrates. Management: Avoid concomitant use of OAT1/3 substrates in patients receiving the Jynarque brand of tolvaptan. Concentrations and effects of the OAT1/3 substrate would be expected to increase with combined use. Consider therapy modification

Topiramate: Loop Diuretics may enhance the hypokalemic effect of Topiramate. Monitor therapy

Xipamide: May enhance the adverse/toxic effect of Loop Diuretics. Specifically, the risk of hypovolemia, electrolyte disturbances, and prerenal azotemia may be increased. Monitor therapy

Yohimbine: May diminish the antihypertensive effect of Antihypertensive Agents. Monitor therapy

Test Interactions

May lead to false-negative aldosterone/renin ratio (ARR) (Funder 2016).

Adverse Reactions

Frequency not defined:

Cardiovascular: Necrotizing angiitis, orthostatic hypotension, thrombophlebitis, vasculitis

Central nervous system: Dizziness, headache, paresthesia, restlessness, vertigo

Dermatologic: Acute generalized exanthematous pustulosis, bullous pemphigoid, erythema multiforme, exfoliative dermatitis, pruritus, skin photosensitivity, skin rash, Stevens-Johnson syndrome, toxic epidermal necrolysis, urticaria

Endocrine & metabolic: Glycosuria, hyperglycemia, hyperuricemia, increased serum cholesterol, increased serum triglycerides

Gastrointestinal: Abdominal cramps, anorexia, constipation, diarrhea, gastric irritation, mouth irritation, nausea, pancreatitis, vomiting

Genitourinary: Bladder spasm

Hematologic & oncologic: Agranulocytosis, anemia, aplastic anemia, eosinophilia, hemolytic anemia, leukopenia, purpura, thrombocytopenia

Hepatic: Hepatic encephalopathy, intrahepatic cholestatic jaundice, liver enzymes increased

Hypersensitivity: Anaphylaxis, anaphylactoid reaction, anaphylactic shock

Immunologic: DRESS syndrome

Neuromuscular & skeletal: Muscle spasm, weakness

Ophthalmic: Blurred vision, xanthopsia

Otic: Deafness, tinnitus

Renal: Interstitial nephritis (allergic), renal disease

Miscellaneous: Fever

ALERT: U.S. Boxed Warning

Fluid/electrolyte loss:

Furosemide is a potent diuretic that, if given in excessive amounts, can lead to a profound diuresis with water and electrolyte depletion. Therefore, careful medical supervision is required and dose and dose schedule must be adjusted to the individual patient's needs.

Warnings/Precautions

Concerns related to adverse effects:

• Fluid/electrolyte loss: [US Boxed Warning]: If given in excessive amounts, furosemide, similar to other loop diuretics, can lead to profound diuresis, resulting in fluid and electrolyte depletion. Close medical supervision and dose evaluation are required. Watch for and correct electrolyte disturbances; adjust dose to avoid dehydration. When electrolyte depletion is present, therapy should not be initiated unless serum electrolytes, especially potassium, are normalized. Risk of hypokalemia may be increased by: rapid diuresis, poor oral potassium intake, cirrhosis, and combined use with large amounts of licorice, corticosteroids, or laxatives (chronic use). In contrast to thiazide diuretics, a loop diuretic can also lower serum calcium concentrations. Electrolyte disturbances can predispose a patient to serious cardiac arrhythmias.

• Hyperuricemia: Asymptomatic hyperuricemia has been reported with use; rarely, may precipitate gout.

• Nephrotoxicity: Monitor fluid status and renal function in an attempt to prevent oliguria, azotemia, and reversible increases in BUN and creatinine; close medical supervision of aggressive diuresis required. May increase risk of radiocontrast-induced nephropathy in high-risk patients.

• Ototoxicity: Rapid IV administration, severe renal impairment, excessive doses, hypoproteinemia, and concurrent use of other ototoxins is associated with ototoxicity.

• Photosensitivity: Photosensitization may occur.

• Sulfonamide (“sulfa”) allergy: The approved product labeling for many medications containing a sulfonamide chemical group includes a broad contraindication in patients with a prior allergic reaction to sulfonamides. There is a potential for cross-reactivity between members of a specific class (eg, two antibiotic sulfonamides). However, concerns for cross-reactivity have previously extended to all compounds containing the sulfonamide structure (SO2NH2). An expanded understanding of allergic mechanisms indicates cross-reactivity between antibiotic sulfonamides and nonantibiotic sulfonamides may not occur or at the very least this potential is extremely low (Brackett 2004; Johnson 2005; Slatore 2004; Tornero 2004). In particular, mechanisms of cross-reaction due to antibody production (anaphylaxis) are unlikely to occur with nonantibiotic sulfonamides. T-cell-mediated (type IV) reactions (eg, maculopapular rash) are less well understood and it is not possible to completely exclude this potential based on current insights. In cases where prior reactions were severe (Stevens-Johnson syndrome/toxic epidermal necrolysis), some clinicians choose to avoid exposure to these classes.

• Thyroid effects: Doses >80 mg may result in transient increase in free thyroid hormones, followed by an overall decrease in total thyroid hormone levels.

Disease-related concerns:

• Adrenal insufficiency: Avoid use of diuretics for treatment of elevated blood pressure in patients with primary adrenal insufficiency (Addison disease). Adjustment of glucocorticoid/mineralocorticoid therapy and/or use of other antihypertensive agents is preferred to treat hypertension (Bornstein 2016; Inder 2015).

• Bariatric surgery: Dehydration: Avoid diuretics in the immediate postoperative period after bariatric surgery; electrolyte disturbances and dehydration may occur. Diuretics may be resumed, if indicated, once oral fluid intake goals are met (Ziegler 2009).

• Cirrhosis: In cirrhosis, avoid electrolyte and acid/base imbalances that might lead to hepatic encephalopathy; correct electrolyte and acid/base imbalances prior to initiation when hepatic coma is present. Supplemental potassium or an aldosterone antagonist, when appropriate, may reduce risk of hypokalemia and metabolic alkalosis. Close monitoring warranted, especially with initiation of therapy.

• Diabetes: Use with caution in patients with prediabetes or diabetes mellitus; may see a change in glucose control.

• Prostatic hyperplasia/urinary stricture: May cause urinary retention due to increased urine production, especially upon initiation of therapy.

• Systemic lupus erythematosus: May cause systemic lupus erythematosus exacerbation or activation.

Special populations:

• Pediatric: May lead to nephrocalcinosis or nephrolithiasis in premature infants and in infants and children <4 years of age with chronic use. May prevent closure of patent ductus arteriosus in premature infants.

• Surgical patients: If given the morning of surgery, furosemide may render the patient volume depleted and blood pressure may be labile during general anesthesia.

Dosage form specific issues:

• Propylene glycol: Some dosage forms may contain propylene glycol; large amounts are potentially toxic and have been associated hyperosmolality, lactic acidosis, seizures, and respiratory depression; use caution (AAP 1997; Zar 2007).

Other warnings and precautions:

• Diuretic resistance: For some patients, despite higher doses of loop diuretic treatment, an adequate diuretic response cannot be attained. Diuretic resistance can usually be overcome by IV administration or the use of two diuretics together (eg, furosemide plus a thiazide). When IV furosemide or multiple diuretics are used, serum electrolytes need to be monitored even more closely (ACC/AHA [Yancy 2013]; Cody 1994).

Monitoring Parameters

Monitor fluid intake and output (inpatient setting) and weight daily; blood pressure, orthostasis; serum electrolytes, renal function; monitor hearing with high doses or rapid IV administration

Pregnancy Considerations

Furosemide crosses the placenta (Beerman 1978; Riva 1978).

Monitor fetal growth if used during pregnancy (ESC [Regitz-Zagrosek 2018]).

Chronic maternal hypertension is associated with adverse events in the fetus/infant. The risk of birth defects, low birth weight, premature delivery, stillbirth, and neonatal death may be increased with chronic hypertension in pregnancy. Actual risks may be related to duration and severity of maternal hypertension. If a diuretic is needed for the treatment of hypertension in pregnancy, other agents are preferred (ACOG 203 2019). Low dose furosemide may be considered in patients with preeclampsia and oliguria (ESC [Regitz-Zagrosek 2018]).

The treatment of edema associated with chronic heart failure during pregnancy is similar to that of nonpregnant patients. Use of diuretics may be considered but use with caution due to the potential reduction in placental blood flow. Patients diagnosed after delivery can be treated according to heart failure guidelines (ESC [Bauersachs 2016]; ESC [Regitz-Zagrosek 2018]).

Patient Education

What is this drug used for?

• It is used to get rid of extra fluid.

• It is used to treat high blood pressure.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Constipation

• Lack of appetite

• Abdominal cramps

• Diarrhea

• Nausea

• Vomiting

• Headache

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Fluid and electrolyte problems like mood changes, confusion, muscle pain or weakness, abnormal heartbeat, severe dizziness, passing out, fast heartbeat, increased thirst, seizures, loss of strength and energy, lack of appetite, unable to pass urine or change in amount of urine passed, dry mouth, dry eyes, nausea, or vomiting.

• High blood sugar like confusion, fatigue, increased thirst, increased hunger, passing a lot of urine, flushing, fast breathing, or breath that smells like fruit.

• Liver problems like dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin.

• Kidney problems like unable to pass urine, blood in the urine, change in amount of urine passed, or weight gain.

• Pancreatitis like severe abdominal pain, severe back pain, severe nausea, or vomiting.

• Infection

• Severe dizziness

• Passing out

• Burning or numbness feeling

• Blurred vision

• Agitation

• Severe loss of strength and energy

• Bruising

• Bleeding

• Noise or ringing in the ears

• Trouble hearing

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.