Furosemide (fyoor OH se mide)
Medication Safety Issues
Sound-alike/look-alike issues:
Furosemide may be confused with torsemide
Lasix® may be confused with Esidrix®, Lanoxin®, Lidex®, Lomotil®, Luvox®, Luxiq®
International issues:
Urex® [Australia] may be confused with Eurax® which is a brand name for crotamiton in the U.S.
Urex® [Australia]: Brand name for methenamine in the U.S.
U.S. Brand Names Lasix®
Canadian Brand Names Apo-Furosemide®; Dom-Furosemide; Furosemide Injection, USP; Furosemide Special; Lasix®; Lasix® Special; Novo-Semide; Nu-Furosemide; PMS-Furosemide
Pharmacologic Category Diuretic, Loop
Use: Labeled Indications Management of edema associated with congestive heart failure and hepatic or renal disease; alone or in combination with antihypertensives in treatment of hypertension
Dosing: Adults
Edema, CHF, or hypertension (diuresis):
Oral: 20-80 mg/dose initially increased in increments of 20-40 mg/dose at intervals of 6-8 hours; usual maintenance dose interval is twice daily or every day
Usual dosage range for hypertension (JNC 7): 20-80 mg/day in 2 divided doses
I.M., I.V.: 20-40 mg/dose, may be repeated in 1-2 hours as needed and increased by 20 mg/dose with each succeeding dose up to 1000 mg/day; usual dosing interval: 6-12 hours. Note: ACC/AHA 2005 guidelines for chronic congestive heart failure recommend a maximum single dose of 160-200 mg.
Continuous I.V. infusion: Initial I.V. bolus dose 20-40 mg, followed by continuous I.V. infusion doses of 10-40 mg/hour. If urine output is < 1 mL/kg/hour, double as necessary to a maximum of 80-160 mg/hour. The risk associated with higher infusion rates (80-160 mg/hour) must be weighed against alternative strategies. Note: ACC/AHA 2005 guidelines for chronic congestive heart failure recommend 40 mg I.V. load, then 10-40 mg/hour infusion.
Refractory heart failure: Oral, I.V.: Doses up to 8 g/day have been used.
Dosing: Elderly, I.M., I.V.: Initial: 20 mg/day; increase slowly to desired response.
Dosing: Pediatric
Edema, CHF, or hypertension (diuresis): Infants and Children:
Oral: 0.5-2 mg/kg/dose increased in increments of 1 mg/kg/dose with each succeeding dose until a satisfactory effect is achieved to a maximum of 6 mg/kg/dose no more frequently than 6 hours
I.M., I.V.: 1 mg/kg/dose, increasing by each succeeding dose at 1 mg/kg/dose at intervals of 6-12 hours until a satisfactory response up to 6 mg/kg/dose
Dosing: Renal Impairment
Acute renal failure: Doses up to 1-3 g/day may be necessary to initiate desired response; avoid use in oliguric states.
Not removed by hemo- or peritoneal dialysis; supplemental dose is not necessary.
Dosing: Hepatic Impairment Diminished natriuretic effect with increased sensitivity to hypokalemia and volume depletion in cirrhosis. Monitor effects, particularly with high doses.
Administration: I.V. I.V. injections should be given slowly. In adults, undiluted direct I.V. injections may be administered at a rate of 40 mg over 1-2 minutes; maximum rate of administration for IVPB or continuous infusion: 4 mg/minute. In children, a maximum rate of 0.5 mg/kg/minute has been recommended.
Administration: I.V. Detail As a general guideline, I.V. bolus doses may be infused at a rate <20 mg/minute. pH: 8-9.3
Administration: Oral May be taken with or without food.
Dietary Considerations May cause a potassium loss; potassium supplement or dietary changes may be required. Administer on an empty stomach. May be administered with food or milk if GI distress occurs. Do not mix with acidic solutions.
Storage Furosemide injection should be stored at controlled room temperature and protected from light. Exposure to light may cause discoloration. Do not use furosemide solutions if they have a yellow color. Refrigeration may result in precipitation or crystallization, however, resolubilization at room temperature or warming may be performed without affecting the drugs stability. I.V. infusion solution mixed in NS or D5W solution is stable for 24 hours at room temperature.
Reconstitution I.V. infusion solution may also be diluted for infusion 1-2 mg/mL (maximum: 10 mg/mL) over 10-15 minutes (following infusion rate parameters).
Compatibility Stable in D5LR, D5NS, D5W, D10W, D20W, mannitol 20%, LR, NS.
Y-site administration: Incompatible with alatrofloxacin, amiodarone, amsacrine, chlorpromazine, ciprofloxacin, clarithromycin, diltiazem, droperidol, esmolol, filgrastim, fluconazole, gatifloxacin, gemcitabine, gentamicin, hydralazine, idarubicin, levofloxacin, metoclopramide, midazolam, milrinone, netilmicin, nicardipine, ondansetron, quinidine gluconate, thiopental, vecuronium, vinblastine, vincristine, vinorelbine.
Compatibility in syringe: Incompatible with doxapram, doxorubicin, droperidol, metoclopramide, milrinone, vinblastine, vincristine.
Compatibility when admixed: Incompatible with buprenorphine, chlorpromazine, diazepam, dobutamine, erythromycin lactobionate, isoproterenol, meperidine, metoclopramide, netilmicin, prochlorperazine edisylate, promethazine.
Contraindications Hypersensitivity to furosemide, any component, or sulfonylureas; anuria; patients with hepatic coma or in states of severe electrolyte depletion until the condition improves or is corrected
Allergy Considerations Loop Diuretic Allergy
Warnings/Precautions Loop diuretics are potent diuretics; excess amounts can lead to profound diuresis with fluid and electrolyte loss; close medical supervision and dose evaluation are required. Watch for and correct electrolyte disturbances; adjust dose to avoid dehydration. In cirrhosis, avoid electrolyte and acid/base imbalances that might lead to hepatic encephalopathy. Coadministration of antihypertensives may increase the risk of hypotension.
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 is required. Rapid I.V. administration, renal impairment, excessive doses, and concurrent use of other ototoxins is associated with ototoxicity. Asymptomatic hyperuricemia has been reported with use.
Chemical similarities are present among sulfonamides, sulfonylureas, carbonic anhydrase inhibitors, thiazides, and loop diuretics (except ethacrynic acid). Use in patients with sulfonylurea allergy is specifically contraindicated in product labeling, however, a risk of cross-reaction exists in patients with allergy to any of these compounds; avoid use when previous reaction has been severe. Discontinue if signs of hypersensitivity are noted.
Geriatric Considerations Loop diuretics are potent diuretics; excess amounts can lead to profound diuresis with fluid and electrolyte loss; close medical supervision and dose evaluation is required, particularly in the elderly. Severe loss of sodium and/or increase in BUN can cause confusion. For any change in mental status in patients on furosemide, monitor electrolytes and renal function.
Pregnancy Risk Factor C
Pregnancy Considerations Crosses the placenta. Increased fetal urine production, electrolyte disturbances reported. Generally, use of diuretics during pregnancy is avoided due to risk of decreased placental perfusion.
Lactation Enters breast milk/use caution
Breast-Feeding Considerations Crosses into breast milk; may suppress lactation. AAP has NO RECOMMENDATION.
Adverse Reactions Frequency not defined.
Cardiovascular: Acute hypotension, chronic aortitis, necrotizing angiitis, orthostatic hypotension, thrombophlebitis, sudden death from cardiac arrest (with I.V. or I.M. administration)
Central nervous system: Blurred vision, dizziness, fever, headache, lightheadedness, restlessness, vertigo, xanthopsia
Dermatologic: Cutaneous vasculitis, erythema multiforme, exfoliative dermatitis, photosensitivity, pruritus, purpura, rash, urticaria
Endocrine & metabolic: Gout, hyperglycemia, hyperuricemia, hypocalcemia, hypochloremia, hypokalemia, hypomagnesemia, hyponatremia, metabolic alkalosis
Gastrointestinal: Anorexia, constipation, cramping, diarrhea, intrahepatic cholestatic jaundice, ischemia hepatitis, nausea, oral and gastric irritation, pancreatitis, vomiting
Genitourinary: Urinary bladder spasm, urinary frequency
Hematological: Agranulocytosis (rare), anemia, aplastic anemia (rare), hemolytic anemia, leukopenia, purpura, thrombocytopenia
Neuromuscular & skeletal: Muscle spasm, paresthesia, weakness
Otic: Hearing impairment (reversible or permanent with rapid I.V. or I.M. administration), reversible deafness (with rapid I.V. or I.M. administration), tinnitus
Renal: Allergic interstitial nephritis, fall in glomerular filtration rate and renal blood flow (due to overdiuresis), glycosuria, transient rise in BUN, vasculitis
Miscellaneous: Anaphylaxis (rare), exacerbate or activate systemic lupus erythematosus
Oncology: Vesicant No
Oncology: Emetic Potential Very low (<10%)
Drug Interactions
ACE Inhibitors: Loop Diuretics may enhance the hypotensive effect of ACE Inhibitors. Specifically, postural hypotension which can accompany ACE Inhibitor initiation. Loop Diuretics may enhance the nephrotoxic effect of ACE Inhibitors. Risk C: Monitor therapy
Aliskiren: May decrease the serum concentration of Furosemide. Risk C: 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 Oxypurinolol, an active metabolite of Allopurinol. Risk C: Monitor therapy
Aminoglycosides: Loop Diuretics may enhance the adverse/toxic effect of Aminoglycosides. Specifically, nephrotoxicity and ototoxicity. Risk C: Monitor therapy
Bile Acid Sequestrants: May decrease the absorption of Loop Diuretics. Risk D: Consider therapy modification
Corticosteroids (Orally Inhaled): May enhance the hypokalemic effect of Loop Diuretics. Risk C: Monitor therapy
Corticosteroids (Systemic): May enhance the hypokalemic effect of Loop Diuretics. Risk C: Monitor therapy
Diazoxide: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
Dofetilide: Loop Diuretics may enhance the QTc-prolonging effect of Dofetilide. Risk C: Monitor therapy
Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy
Herbs (Hypotensive Properties): May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
Methylphenidate: May diminish the antihypertensive effect of Antihypertensives. Risk C: 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. Risk C: Monitor therapy
Nonsteroidal Anti-Inflammatory Agents: May diminish the diuretic effect of Loop Diuretics. Risk C: Monitor therapy
Phenytoin: May diminish the diuretic effect of Loop Diuretics. Risk C: Monitor therapy
Prostacyclin Analogues: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy
Rituximab: Antihypertensives may enhance the hypotensive effect of Rituximab. Risk D: Consider therapy modification
Ethanol/Nutrition/Herb Interactions
Food: Furosemide serum levels may be decreased if taken with food.
Herb/Nutraceutical: Avoid dong quai if using for hypertension (has estrogenic activity). Avoid ephedra, yohimbe, and ginseng (may worsen hypertension). Limit intake of natural licorice. Avoid garlic (may have increased antihypertensive effect).
Monitoring Parameters Monitor weight and I & O daily; blood pressure, orthostasis, serum electrolytes, renal function; in high doses, monitor hearing
Nursing: Physical Assessment/Monitoring Assess for allergy to sulfonylurea before beginning therapy. Assess potential for interactions with other pharmacological agents or herbal products patient may be taking (especially anything that may impact fluid balance, electrolyte balance, or increase potential for ototoxicity or hypotension). For intravenous use, see Administration specifics. Assess results of laboratory tests (electrolytes), therapeutic effectiveness, and adverse response on a regular basis during therapy (eg, dehydration, electrolyte imbalance, postural hypotension). Caution patients with diabetes about closely monitoring glucose levels (glucose tolerance may be decreased). Teach patient appropriate use, possible side effects/appropriate interventions, and adverse symptoms to report.
Monitoring: Lab Tests Serum electrolytes, renal function
Patient Education Do not take any new medication during therapy unless approved by prescriber. Take as directed with food or milk (to reduce GI distress) early in the day (daily), or if twice daily, take last dose in late afternoon in order to avoid sleep disturbance and achieve maximum therapeutic effect. Keep medication in original container, away from light; do not use discolored medication. Follow dietary advice of prescriber; include bananas or orange juice or other potassium-rich foods in daily diet. Do not take potassium supplements without advice of prescriber. If you have diabetes, monitor glucose levels closely (this medication may alter glucose tolerance requiring an adjustment in the dose of hypoglycemic agent). Weigh yourself each day, at the same time, in the same clothes when beginning therapy and weekly on long-term therapy. Report unusual or unanticipated weight gain or loss. May cause dizziness, blurred vision, or drowsiness (use caution when driving or engaging in tasks that require alertness until response to drug is known); postural hypotension (use caution when rising from lying or sitting position or when climbing stairs); or sensitivity to sunlight (use sunblock or wear protective clothing and sunglasses). Report signs of edema (eg, weight gains; swollen ankles, feet, or hands), trembling, numbness or fatigue, cramping or muscle weakness, palpitations, unresolved nausea or vomiting, or change in hearing. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to become pregnant. Consult prescriber if breast-feeding.
Available Dosage Forms
Injection, solution: 10 mg/mL (2 mL, 4 mL, 8 mL, 10 mL)
Solution, oral: 10 mg/mL, 40 mg/5 mL
Tablet: 20 mg, 40 mg, 80 mg
Lasix®: 20 mg, 40 mg, 80 mg
Generic Available Yes
Pricing: U.S. (www.drugstore.com)
Solution (Furosemide)
10 mg/mL (60): $16.99
10 mg/mL (120): $15.98
Tablets (Furosemide)
20 mg (100): $13.99
40 mg (100): $13.99
80 mg (30): $12.99
Tablets (Lasix)
20 mg (30): $20.60
40 mg (30): $23.86
80 mg (30): $30.37
Mechanism of Action Inhibits reabsorption of sodium and chloride in the ascending loop of Henle and distal renal tubule, interfering with the chloride-binding cotransport system, thus causing increased excretion of water, sodium, chloride, magnesium, and calcium
Pharmacodynamics/Kinetics
Onset of Action Diuresis: Oral: 30-60 minutes; I.M.: 30 minutes; I.V.: ~5 minutes; Peak effect: Oral: 1-2 hours
Duration of Action Oral: 6-8 hours; I.V.: 2 hours
Absorption Oral: 60% to 67%
Protein Binding >98%
Half-Life Elimination Normal renal function: 0.5-1.1 hours; End-stage renal disease: 9 hours
Metabolism Minimally hepatic
Excretion Urine (Oral: 50%, I.V.: 80%) within 24 hours; feces (as unchanged drug); nonrenal clearance prolonged with renal impairment
Dental Health: Effects on Dental Treatment No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions No information available to require special precautions
Mental Health: Effects on Mental Status Dizziness is common
Mental Health: Effects on Psychiatric Treatment Orthostatic hypotension is common; use caution with low potency antipsychotics and TCAs; may rarely cause agranulocytosis; caution with clozapine and carbamazepine; may decrease renal clearance of lithium resulting in elevated serum levels and risk for toxicity; more common with thiazide diuretics; monitor lithium levels
Cardiovascular Considerations It is important that patients be closely followed for hypokalemia, hypomagnesemia, and volume depletion because of significant diuresis.
Anesthesia and Critical Care Concerns/Other Considerations It is important that patients be closely followed for hypokalemia, hypomagnesemia, and volume depletion because of significant diuresis. If given the morning of surgery, it may render the patient volume depleted and blood pressure may be labile during general anesthesia.
Index Terms Frusemide
