Furosemideinteractions

Aminoglycoside antibiotics: Increased potential ototoxicity of the antibiotics.

Avoid combination Ethacrynic acid: Risk of ototoxicity.

Avoid combination Salicylates: Risk of salicylate toxicity Cisplatin and nephrotoxic drugs: Risk of ototoxicity and nephrotoxicity Lithium: Risk of lithium toxicity Renin-angiotensin inhibitors: Increased risk of hypotension and renal failure.

Adrenergic blocking drugs: Risk of potentiation Drugs undergoing renal tubular secretion: Risk of toxicity potentiation

7.1 Effects of

Furosemide on Other Drugs Drug/Substance Class or Name Drug Interaction Effect Recommendations Aminoglycoside antibiotics Furosemide may increase the ototoxic potential of aminoglycoside antibiotics, especially in the presence of impaired renal function. Avoid combination except in life-threatening situations. Ethacrynic acid Possibility of ototoxicity. Avoid concomitant use with ethacrynic acid. Salicylates May experience salicylate toxicity at lower doses because of competitive renal excretory sites. Monitor for symptoms of salicylate toxicity. Cisplatin There is a risk of ototoxic effects if cisplatin and furosemide are given concomitantly. Cisplatin and nephrotoxic drugs Nephrotoxicity Administer furosemide at lower doses and with positive fluid balance when used to achieve forced diuresis during cisplatin treatment. Monitor renal function. Paralytic agents Furosemide has a tendency to antagonize the skeletal muscle relaxing effect of tubocurarine and may potentiate the action of succinylcholine. Monitor for skeletal muscle effect. Lithium Furosemide reduces lithium’s renal clearance and add a high-risk of lithium toxicity. Avoid concomitant use with lithium. Angiotensin converting enzyme inhibitors or angiotensin II receptor blockers May lead to severe hypotension and deterioration in renal function, including renal failure. Monitor for changes in blood pressure and renal function and interrupt or reduce the dosage of furosemide, angiotensin converting enzyme inhibitors, or angiotensin receptor blockers if needed. Antihypertensive drugs Furosemide may add to or potentiate the therapeutic effect of other antihypertensive drugs. Monitor for changes in blood pressure and adjust the dose of other antihypertensive drugs if needed. Adrenergic blocking drugs or peripheral adrenergic blocking drugs Potentiation occurs. Monitor for changes in blood pressure and adjust the dose of adrenergic blocking drugs if needed. Norepinephrine Furosemide may decrease arterial responsiveness (vasoconstricting effect) to norepinephrine. Monitor blood pressure (or mean arterial pressure). Chloral hydrate 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. Concomitant use with chloral hydrate is not recommended. Methotrexate and other drugs undergoing renal tubular secretion Furosemide may decrease renal elimination of other drugs that undergo tubular secretion. High-dose treatment of furosemide may result in elevated serum levels of these drugs and may potentiate their toxicity. Monitor serum levels of drugs undergoing renal tubular secretion and adjust the dose if needed. Cephalosporin Furosemide can increase the risk of cephalosporin-induced nephrotoxicity even in the setting of minor or transient renal impairment. Monitor for changes in renal function. Cyclosporine Increased risk of gouty arthritis secondary to furosemide-induced hyperuricemia and cyclosporine impairment of renal urate excretion. Monitor serum urate levels. Thyroid hormones 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. Monitor the total thyroid hormone levels.

7.2 Effects of

Other Drugs on Furosemide Drug/Substance Class or Name Drug Interaction Effect Recommendations Phenytoin Interferes directly with renal action of furosemide. Monitor diuretic effects of furosemide and adjust the dose of furosemide if needed. Methotrexate and other drugs undergoing renal tubular secretion May reduce the effect of furosemide. High-dose treatment of methotrexate and these other drugs may result in elevated serum levels of furosemide and may potentiate the toxicity of furosemide. Monitor for enhanced toxicity of furosemide. Indomethacin 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.