Furosemide

Brand names: Lasix, Furosemide, FUROSEMIDE, FUROSCIX, LASIX ONYU

Boxed warning

WARNING Furosemide is a potent diuretic which, 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. (See DOSAGE AND ADMINISTRATION .)

Warnings

BOXED WARNING: BOXED WARNING: LASIX is a potent diuretic that "if given in excessive amounts, can lead to a profound diuresis with water and electrolyte depletion." Careful medical supervision and individualized dosing are required. Key Warnings: - Risk of severe dehydration and electrolyte imbalances (hypokalemia, hyponatremia) - Ototoxicity (hearing loss/tinnitus), especially with rapid IV injection or renal impairment - In liver cirrhosis: sudden fluid/electrolyte shifts may precipitate hepatic coma - Hyperglycemia and diabetes precipitation possible - Acute urinary retention risk in patients with urinary obstruction ---

Contraindications

CONTRAINDICATIONS Furosemide tablets are contraindicated in patients with anuria and in patients with a history of hypersensitivity to furosemide.

Overdose

OVERDOSAGE The principal signs and symptoms of overdose with furosemide are dehydration, blood volume reduction, hypotension, electrolyte imbalance, hypokalemia and hypochloremic alkalosis, and are extensions of its diuretic action. The acute toxicity of furosemide has been determined in mice, rats and dogs. In all three, the oral LD 50 exceeded 1000 mg/kg body weight, while the intravenous LD 50 ranged from 300 to 680 mg/kg. The acute intragastric toxicity in neonatal rats is 7 to 10 times that of adult rats. The concentration of furosemide in biological fluids associated with toxicity or death is not known. Treatment of overdosage is supportive and consists of replacement of excessive fluid and electrolyte losses. Serum electrolytes, carbon dioxide level and blood pressure should be determined frequently. Adequate drainage must be assured in patients with urinary bladder outlet obstruction (such as prostatic hypertrophy). Hemodialysis does not accelerate furosemide elimination.

Drug interactions

Drug Interactions Furosemide may increase the ototoxic potential of aminoglycoside antibiotics, especially in the presence of impaired renal function. Except in life-threatening situations, avoid this combination. Furosemide should not be used concomitantly with ethacrynic acid because of the possibility of ototoxicity. Patients receiving high doses of salicylates concomitantly with furosemide, as in rheumatic disease, may experience salicylate toxicity at lower doses because of competitive renal excretory sites. There is a risk of ototoxic effects if cisplatin and furosemide are given concomitantly. In addition, nephrotoxicity of nephrotoxic drugs such as cisplatin may be enhanced if furosemide is not given in lower doses and with positive fluid balance when used to achieve forced diuresis during cisplatin treatment. Furosemide has a tendency to antagonize the skeletal muscle relaxing effect of tubocurarine and may potentiate the action of succinylcholine. Lithium generally should not be given with diuretics because they reduce lithium's renal clearance and add a high risk of lithium toxicity. Furosemide combined with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers may lead to severe hypotension and deterioration in renal function, including renal failure. An interruption or reduction in the dosage of furosemide, angiotensin converting enzyme inhibitors, or angiotensin receptor blockers may be necessary. Potentiation occurs with ganglionic or peripheral adrenergic blocking drugs. Furosemide may decrease arterial responsiveness to norepinephrine. However, norepinephrine may still be used effectively. Simultaneous administration of sucralfate and furosemide tablets may reduce the natriuretic and antihypertensive effects of furosemide. Patients receiving both drugs should be observed closely to determine if the desired diuretic and/or antihypertensive effect of furosemide is achieved. The intake of furosemide and sucralfate should be separated by at least two hours. In isolated cases, intravenous administration of furosemide within 24 hours of taking chloral hydrate may lead to flushing, sweating attacks, restlessness, nausea, increase in blood pressure, and tachycardia. Use of furosemide concomitantly with chloral hydrate is therefore not recommended. Phenytoin interferes directly with renal action of furosemide. There is evidence that treatment with phenytoin leads to decrease intestinal absorption of furosemide, and consequently to lower peak serum furosemide concentrations. Methotrexate and other drugs that, like furosemide, undergo significant renal tubular secretion may reduce the effect of furosemide. Conversely, 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 of these drugs and may potentiate their toxicity as well as the toxicity of furosemide. Furosemide can increase the risk of cephalosporin-induced nephrotoxicity even in the setting of minor or transient renal impairment. Concomitant use of cyclosporine and furosemide is associated with increased risk of gouty arthritis secondary to furosemide-induced hyperurecemia and cyclosporine impairment of renal urate excretion. High doses (> 80 mg) of furosemide may inhibit the binding of thyroid hormones to carrier proteins and result in transient increase in free thyroid hormones, followed by an overall decrease in total thyroid hormone levels. One study in six subjects demonstrated that the combination of furosemide and acetylsalicylic acid temporarily reduced creatinine clearance in patients with chronic renal insufficiency. There are case reports of patients who developed increased BUN, serum creatinine and serum potassium levels, and weight gain when furosemide was used in conjunction with NSAIDs. Literature reports indicate that coadministration of indomethacin may reduce the natriuretic and antihypertensive effects of furosemide in some patients by inhibiting prostaglandin synthesis. Indomethacin may also affect plasma renin levels, aldosterone excretion, and renin profile evaluation. Patients receiving both indomethacin and furosemide should be observed closely to determine if the desired diuretic and/or antihypertensive effect of furosemide is achieved.

Uses

Edema: LASIX treats edema associated with congestive heart failure, liver cirrhosis, and renal disease, particularly when "an agent with greater diuretic potential is desired." Hypertension: Oral LASIX may be used alone or combined with other antihypertensive agents for treating high blood pressure in adults. The label notes that patients inadequately controlled with thiazides will likely not respond adequately to LASIX monotherapy. ---

Dosage forms & strengths

Tablet INJECTION, SOLUTION TABLET INJECTION POWDER SOLUTION

FUROSEMIDE 20 mg FUROSEMIDE 40 mg FUROSEMIDE 80 mg Furosemide 20 mg furosemide 80 mg FUROSEMIDE 10 mg/mL FUROSEMIDE 40 mg/1 FUROSEMIDE 80 mg/1 FUROSEMIDE 20 mg/1 FUROSEMIDE 1 kg/kg FUROSEMIDE 40 mg/5mL FUROSEMIDE 1 g/g FUROSEMIDE 20 mg/2mL FUROSEMIDE 40 mg/4mL FUROSEMIDE 50 kg/50kg FUROSEMIDE 80 mg/mL FUROSEMIDE 100 g/100g FUROSEMIDE 100 mg/10mL FUROSEMIDE 8 mg/mL FUROSEMIDE 100 kg/100kg FUROSEMIDE 30 mg/mL

DOSAGE AND ADMINISTRATION Edema Therapy should be individualized according to patient response to gain maximal therapeutic response and to determine the minimal dose needed to maintain that response. Adults: The usual initial dose of furosemide tablets is 20 to 80 mg given as a single dose. Ordinarily a prompt diuresis ensues. If needed, the same dose can be administered 6 to 8 hours later or the dose may be increased. The dose may be raised by 20 or 40 mg and given not sooner than 6 to 8 hours after the previous dose until the desired diuretic effect has been obtained. The individually determined single dose should then be given once or twice daily (e.g., at 8 am and 2 pm). The dose of furosemide tablets may be carefully titrated up to 600 mg/day in patients with clinically severe edematous states. Edema may be most efficiently and safely mobilized by giving furosemide tablets on 2 to 4 consecutive days each week. When doses exceeding 80 mg/day are given for prolonged periods, careful clinical observation and laboratory monitoring are particularly advisable (see PRECAUTIONS: Laboratory Tests ). Geriatric Patients: In general, dose selection for the elderly patient should be cautious, usually starting at the low end of the dosing range (see PRECAUTIONS: Geriatric Use ). Pediatric Patients: The usual initial dose of oral furosemide in pediatric patients is 2 mg/kg body weight, given as a single dose. If the diuretic response is not satisfactory after the initial dose, dosage may be increased by 1 or 2 mg/kg no sooner than 6 to 8 hours after the previous dose. Doses greater than 6 mg/kg body weight are not recommended. For maintenance therapy in pediatric patients, the dose should be adjusted to the minimum effective level. Hypertension Therapy should be individualized according to the patient's response to gain maximal therapeutic response and to determine the minimal dose needed to maintain the therapeutic response. Adults: The usual initial dose of furosemide tablets for hypertension is 80 mg, usually divided into 40 mg twice a day. Dosage should then be adjusted according to response. If response is not satisfactory, add other antihypertensive agents. Changes in blood pressure must be carefully monitored when furosemide tablets are used with other antihypertensive drugs, especially during initial therapy. To prevent excessive drop in blood pressure, the dosage of other agents should be reduced by at least 50 percent when furosemide tablets are added to the regimen. As the blood pressure falls under the potentiating effect of furosemide tablets, a further reduction in dosage or even discontinuation of other antihypertensive drugs may be necessary. Geriatric Patients: In general, dose selection and dose adjustment for the elderly patient should be cautious, usually starting at the low end of the dosing range (see PRECAUTIONS: Geriatric Use ).