Furosemide with Tobramycin Interaction Details
Brand Names Associated with Furosemide
- Furosemide
- Lasix®
Brand Names Associated with Tobramycin
- Nebcin®
- Tobramycin Injection
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 10, 2023
Interaction Effect
Increased tobramycin plasma and tissue concentrations and additive ototoxicity and/or nephrotoxicity
Interaction Summary
Concomitant use of furosemide and tobramycin should be avoided due to potential additive nephrotoxicity and ototoxicity except in life-threatening situations . Avoid excessive doses of either drug, especially in uremic patients, as there is evidence to suggest that renal dysfunction will increase the risk of ototoxicity Concurrent administration of IV furosemide may increase tobramycin toxicity by altering tobramycin serum and tissue concentrations . Coadministration of tobramycin and furosemide may increase risk of ototoxicity, especially in the presence of impaired renal function .
Severity
Major
Onset
Unspecified
Evidence
Probable
How To Manage Interaction
The concomitant use of furosemide and tobramycin should be avoided due to potential additive nephrotoxicity and ototoxicity except in life-threatening situations . Avoid excessive doses of either drug, especially in uremic patients, as there is evidence to suggest that renal dysfunction will increase the risk of ototoxicity . Concurrent administration of IV furosemide may increase tobramycin toxicity by altering tobramycin serum and tissue concentrations . Coadministration of tobramycin and furosemide may increase the risk of ototoxicity, especially in the presence of impaired renal function .
Mechanism Of Interaction
Additive or synergistic toxicity
Literature Reports
A) A 70-year-old woman with a history of congestive heart failure was treated with tobramycin following sputum gram stain results indicating gram-negative bacilli. Peak and trough levels following a loading dose of tobramycin 150 mg (2 mg/kg) were 3.7 and 1.5 mcg/mL (7.9 and 3.2 mcmol/L), respectively. The volume of distribution (Vd) was determined to be 0.46 L/kg (normal 0.25 L/kg) and half-life 4.6 hours. The maintenance dose was adjusted to 180 mg IV every 8 hours. The patient received a bolus injection of furosemide 120 mg IV 12 hours after the tobramycin loading dose for extensive edema. Peak and trough levels of tobramycin after the fourth dose were 16.2 and 5.3 mcg/mL (34.7 and 11 mcmol/L; Vd 0.18 L/kg; half-life 4 hours). The authors proposed that the increase in tobramycin serum levels resulted from a decrease in edema (decrease in Vd) since the drug distributes well into extracellular fluid .
B) The effects of furosemide-aminoglycoside combination therapy on ototoxicity was studied. As measured by audiograms, toxicity developed in 5 of 23 patients (21.7%) receiving furosemide and aminoglycosides and in 28 of 119 patients (23.5%) who received only an aminoglycoside. However, only a small number of patients received combination therapy, as opposed to single-agent furosemide therapy. Significant differences may have been detected with larger numbers of patients receiving the combination. The same authors also conducted a retrospective study of the influence of furosemide on aminoglycoside-induced nephrotoxicity. Nephrotoxicity was defined as a rise in serum creatinine of greater than or equal to 0.5 mg/dL (40 mcmol/L) if the original concentration was less than 3 mg/dL (300 mcmol/L) or a rise of greater than or equal to 1 mg/dL (90 mcmol/L) if the original concentration was 3 mg/dL (300 mcmol/L) or greater. Results demonstrated nephrotoxicity in 10 of 50 patients (20%) given furosemide and aminoglycoside and in 38 of 222 patients (17.1%) given only an aminoglycoside. The authors concluded that the coadministration of furosemide with aminoglycosides should not be considered a major risk factor for the development of aminoglycoside-induced nephrotoxicity or auditory toxicity .
Furosemide Overview
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Furosemide is used alone or in combination with other medications to treat high blood pressure. Furosemide is used to treat edema (fluid retention; excess fluid held in body tissues) caused by various medical problems, including heart, kidney, and liver disease. Furosemide is in a class of medications called diuretics ('water pills'). It works by causing the kidneys to get rid of unneeded water and salt from the body into the urine.
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High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.
Tobramycin Overview
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Tobramycin injection is used to treat certain serious infections that are caused by bacteria such as meningitis (infection of the membranes that surround the brain and spinal cord) and infections of the blood, abdomen (stomach area), lungs, skin, bones, joints, and urinary tract. Tobramycin injection is in a class of medications called aminoglycoside antibiotics. It works by killing bacteria.
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Antibiotics such as tobramycin injection will not work for colds, flu, or other viral infections. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.
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Definitions
Severity Categories
Contraindicated
These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.
Major
This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.
Moderate
This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.
Minor
While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.
Onset
Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.
Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.
Evidence
Level of documentation of the interaction.
Established: The interaction is documented and substantiated in peer-reviewed medical literature.
Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.
How To Manage The Interaction
Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.
It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.
Mechanism Of Interaction
The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.
Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.
Where Does Our Information Come From?
Information for our drug interactions is compiled from several drug compendia, including:
The prescribing information for each drug, as published on DailyMED, is also used.
Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.
The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.