FUROSEMIDE 
Pronounciation
- (fur-OH-seh-myd)
Trade Name(s)
- Lasix
Adjust dose and dose schedule to individual patient needs. Reserve parenteral therapy for emergent situations or for patients unable to take oral therapy. Switch to oral therapy as soon as practical.
Patient assessment may be indicated; see Precautions.
20 to 40 mg. May be repeated in 2 hours. If necessary, increase dosage by 20-mg increments (under close medical supervision and no sooner than 2 hours after previous dose) until desired diuresis is obtained. After the initial diuresis the minimum effective dose may be given once or twice every 24 hours as required for maintenance.
40 mg. Dose may be increased to 80 mg after 1 hour if satisfactory response is not obtained. AHA guidelines recommend 0.5 mg/kg to 1 mg/kg over 1 to 2 minutes. If no response, increase to 2 mg/kg. For new-onset pulmonary edema with hypovolemia, a dose of less than 0.5 mg/kg is recommended. Additional therapy (e.g., digoxin, oxygen) may be administered concurrently as needed.
Hypertensive crisis (unlabeled):
AHA guidelines recommend 0.5 to 1 mg/kg over 1 to 2 minutes. If no response, increase dose to 2 mg/kg.
See Maternal/Child.
1 mg/kg of body weight. After 2 hours increase by 1-mg/kg increments to effect desired response. Do not exceed 6 mg/kg/dose. Effective dose may be given every 6 to 12 hours. Another source suggests 1 to 2 mg/kg/dose every 6 to 12 hours.
0.5 to 1 mg/kg/dose every 8 to 24 hours. Maximum dose is 2 mg/kg/dose. Literature reports suggest that the maximum dose for premature infants should not exceed 1 mg/kg/day. See Maternal/Child.
Higher doses may be required in renal insufficiency and acute or chronic renal failure. ■ Reduced dose or extended intervals may be appropriate in the elderly. ■ Extend dosing intervals in neonates because half-life is prolonged. ■ See Drug/Lab Interactions.
May be given undiluted. May be given through Y-tube or three-way stopcock of infusion set. Not usually added to IV solutions, but large doses may be added to NS, LR, or D5W and given as an infusion. Another source suggests it can be diluted with D5NS. pH of solution must be over 5.5. Some sources recommend protecting diluted solutions from light to prevent photodegradation (minimized at pH 7).
One source found no significant drug loss when filtered through a 0.22-micron filter.
Store vials at CRT. Protect from light. If diluted for infusion, discard after 24 hours.
Furosemide may precipitate at a pH below 7. Manufacturer states, “Acid solutions, including other parenteral medications (e.g., amrinone, ciprofloxacin, labetalol, milrinone), must not be administered concurrently in the same infusion.” Additionally, “Furosemide should not be added to an IV line containing any of these acidic products.”
Other sources suggest specific compatibilities dependent on concentration and manufacturer; consult a pharmacist.
Each 40 mg or fraction thereof should be given over 1 to 2 minutes.
One source recommends the following: Adults: 0.1 mg/kg/hr. Pediatric patients: 0.05 mg/kg/hr. Titrate to effect. High-dose therapy in an infusion should not exceed a rate of 4 mg/min.
A potent loop diuretic, structurally related to sulfonamides. Onset of action is prompt, usually within 5 minutes. Duration of action and half-life are approximately 2 hours. Inhibits the reabsorption of sodium and chloride in the proximal and distal tubules and in the loop of Henle, causing increased excretion of water, sodium, chloride, magnesium, and calcium. Highly protein bound. Metabolized and excreted in the urine. Crosses the placental barrier. Secreted in breast milk.
Parenteral therapy should be reserved for patients unable to take oral medications or for emergency clinical situations. ■ Edema associated with congestive heart failure, cirrhosis of the liver, and renal disease, including nephrotic syndrome. Particularly useful when an agent with a greater diuretic potential is required. ■ Adjunctive therapy in acute pulmonary edema. Indicated when rapid onset of diuresis is necessary (e.g., acute pulmonary edema).
A potent diuretic; may precipitate excessive diuresis with water and electrolyte depletion. Careful medical supervision is required.■ Use caution and improve basic condition first in hepatic coma, electrolyte depletion, and advanced cirrhosis of the liver. Sudden alterations of fluid and electrolyte balance in patients with cirrhosis may precipitate hepatic coma. Supplemental potassium chloride and, if required, an aldosterone antagonist (e.g., spironolactone) are helpful in preventing hypokalemia and metabolic alkalosis. ■ Excessive diuresis may cause dehydration and blood volume reduction with circulatory collapse and possibly vascular thrombosis and embolism, particularly in the elderly. ■ If increasing azotemia and oliguria develop during treatment of severe progressive renal disease, furosemide should be discontinued. ■ Use caution in known sulfonamide sensitivity. Manufacturer states that patients allergic to sulfonamides may also be allergic to furosemide. However, current literature suggests that the potential for cross-reactivity between antibiotic sulfonamides and nonantibiotic sulfonamides is low. ■ Ototoxicity (tinnitus, reversible or irreversible hearing impairment and deafness) has been reported. Risk increases with higher doses, rapid injection, severe renal dysfunction, hypoproteinemia, or concurrent use with other ototoxic drugs; see Drug/Lab Interactions. ■ In patients with hypoproteinemia (e.g., associated with nephrotic syndrome), the effect of furosemide may be weakened and its ototoxicity potentiated. ■ May activate or exacerbate systemic lupus erythematosus. ■ Use caution in patients with severe symptoms of urinary retention (because of bladder emptying disorders, prostatic hypertrophy, urethral narrowing). May experience acute urinary retention related to increased production and retention of urine. Careful monitoring required, especially during the initiation of therapy.
Monitor BP frequently, especially during initial therapy. ■ May precipitate excessive diuresis with water and electrolyte imbalance (hyponatremia, hypochloremic alkalosis, hypokalemia, hypomagnesemia, or hypocalcemia). Routine checks on electrolyte panel, CO2, SCr, and BUN are necessary during therapy. Electrolyte replacement may be required. ■ May increase blood glucose and has precipitated diabetes mellitus (rare). Monitoring may be indicated, especially in patients with diabetes or suspected latent diabetes. ■ Periodic monitoring of CBC and liver function tests are indicated to monitor for blood dyscrasias or liver damage. ■ Monitor for other S/S of fluid or electrolyte imbalance, which may include arrhythmia, drowsiness, dryness of the mouth, hypotension, lethargy, muscle cramps or fatigue, nausea or vomiting, oliguria, restlessness, tachycardia, thirst, and weakness. ■ May lower serum calcium level; may cause tetany. ■ Hyperuricemia can occur. Rarely precipitates acute gout attack. ■ See Drug/Lab Interactions.
Hypotension may cause dizziness; request assistance with ambulation. ■ Report cramps, dizziness, muscle weakness, or nausea promptly. ■ May cause a decrease in potassium levels and require a supplement. ■ Skin may become photosensitive; avoid unprotected exposure to sun. ■ Therapy for diabetes may require adjustment; monitoring of serum glucose required.
Category C: use during pregnancy only when clearly needed and benefits outweigh potential risks to fetus. Treatment during pregnancy requires monitoring of fetal growth because of the potential for higher fetal birth weights. ■ Use caution in breast-feeding; may inhibit lactation. ■ May precipitate nephrocalcinosis and nephrolithiasis in premature infants. Has also been observed in pediatric patients under 4 years of age who have been treated chronically with furosemide. Monitor renal function. Renal ultrasonography may be indicated. ■ Administration in the first few weeks of life may increase risk of persistent patent ductus arteriosus in preterm infants with respiratory distress syndrome. ■ Premature infants receiving doses exceeding 1 mg/kg/day may develop plasma levels that could be associated with toxicity, including ototoxicity. Hearing loss in neonates has been associated with the use of furosemide.
Protein binding and clearance are decreased in the elderly. ■ Consider increased sensitivity to hypotensive and electrolyte effects. Dose selection should be cautious, starting at the lower end of the dosing range. ■ May be more susceptible to dehydration; observe carefully. ■ Avoid rapid contraction of plasma volume and hemoconcentration. May cause thromboembolic episodes (e.g., CVA, pulmonary emboli). ■ The initial diuretic effect in older patients is decreased relative to younger patients.
Concomitant use with amphotericin B, corticosteroids, ACTH, licorice in large amounts, or prolonged use of laxatives may increase the risk of hypokalemia. ■ Potentiates antihypertensive drugs (e.g., angiotensin II receptor blockers, nitroglycerin, nitroprusside sodium); reduced dose of the antihypertensive agent or both drugs may be indicated. In addition to hypotension, concomitant use with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) may lead to deterioration in renal function, including renal failure. An interruption or reduction in the dose of furosemide, ACEI, or ARB may be necessary. ■ May cause transient or permanent deafness with doses exceeding the usual or when given in conjunction with other ototoxic drugs (e.g., aminoglycosides [e.g., gentamicin], cisplatin), especially in the presence of renal impairment; avoid concomitant use if possible. Do not use concomitantly with ethacrynic acid (Edecrin); risk of ototoxicity markedly increased. ■ Nephrotoxicity increased by other nephrotoxic agents (e.g., aminoglycosides, cephalosporins, cisplatin, cyclosporine, radiocontrast agents, vancomycin). Monitor renal function closely. ■ Diuretics reduce the renal clearance of lithium, increasing the risk of toxicity. ■ May cause cardiac arrhythmias with amiodarone or digoxin (potassium depletion). ■ May enhance or inhibit actions of nondepolarizing muscle relaxants. ■ May potentiate the action of succinylcholine.■ Effects may be inhibited by NSAIDs (e.g., ibuprofen) or probenecid.■ May cause profound diuresis and serious electrolyte abnormalities with thiazide diuretics because of synergistic effects. ■ Furosemide may increase serum levels of salicylates, increasing the risk of toxicity. ■ May decrease arterial responsiveness to norepinephrine. Dose adjustment may be required. ■ May enhance adverse effects of chloral hydrate. Concomitant use not recommended. ■ Methotrexate and other drugs that undergo significant renal tubular secretion may decrease the effectiveness of furosemide. ■ Furosemide may decrease renal elimination of other drugs that undergo tubular secretion. High-dose treatment of both furosemide and these other drugs may result in elevated serum levels and may potentiate toxicity. ■ Concomitant use of cyclosporine and furosemide has been associated with increased risk of gouty arthritis secondary to furosemide-induced hyperuricemia and cyclosporine impairment of renal urate excretion. ■ Simultaneous administration of sucralfate and furosemide injection may reduce the natriuretic and antihypertensive effects of furosemide. Separate doses by at least 2 hours and monitor for desired effect. ■ High doses (greater than 80 mg) of furosemide may inhibit the binding of thyroid hormones to carrier proteins and result in a transient increase in free thyroid hormones followed by an overall decrease in total thyroid hormone levels. ■ See Precautions.
Usually occur in prolonged therapy, seriously ill patients, or following large doses.
The most serious side effects include anaphylactic or anaphylactoid reactions (severe or with shock), aplastic anemia, drug rash with eosinophilia and systemic symptoms (DRESS), erythema multiforme, exanthematous pustulosis (acute, generalized), hepatic encephalopathy in patients with hepatocellular insufficiency, orthostatic hypotension (may be aggravated by alcohol, barbiturates, or narcotics), Stevens-Johnson syndrome, tinnitus and hearing loss, and toxic epidermal necrolysis. Anorexia; blurred vision; bullous pemphigoid; constipation; cramping; diarrhea; dizziness; exfoliative dermatitis; headache; hematologic reactions (agranulocytosis, anemia, eosinophilia, hemolytic anemia, GI cramping, leukopenia, thrombocytopenia); increased cholesterol, liver enzymes, and triglyceride serum levels; interstitial nephritis; jaundice (intrahepatic cholestatic jaundice); nausea; necrotizing angiitis; oral and gastric irritation; pancreatitis; paresthesias; photosensitivity; pruritus; purpura; rash; thrombocytopenia; urticaria; vasculitis (systemic); vertigo; vomiting; and xanthopsia have occurred. Fever, glycosuria, hyperglycemia, hyperuricemia, muscle spasms, restlessness, thrombophlebitis, transient injection site pain following IM injection, urinary bladder spasm, and weakness have also been reported.
Blood volume reduction, dehydration, electrolyte imbalances, hypochloremic alkalosis, and hypotension.
If minor side effects are noted, notify the physician, who may treat the side effects symptomatically and continue the drug. If side effects are progressive or any major side effect occurs, discontinue the drug immediately and notify the physician. Treatment of major side effects is symptomatic and aggressive. Monitor serum electrolytes, carbon dioxide level, and BP frequently, and replace excessive fluid and electrolyte losses as needed. Hemodialysis does not accelerate furosemide elimination. Resuscitate as necessary.