Linezolid with Warfarin Interaction Details
Brand Names Associated with Linezolid
- Linezolid
- Zyvox®
Brand Names Associated with Warfarin
- Coumadin®
- Jantoven®
- Warfarin
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 13, 2023
Interaction Effect
Increased INR
Interaction Summary
Concomitant use of linezolid with warfarin increased the PT/INR from 1.62 to 3 in one retrospective survey and reduce warfarin dose requirements from 3.23 mg/day to 2.69 mg/day in another retrospective study. Consider close PT/INR monitoring during and after concomitant use .
Severity
Major
Onset
Unspecified
Evidence
Theoretical
How To Manage Interaction
Concomitant use of linezolid with warfarin may increase the PT/INR and reduce warfarin dose requirements. Consider close PT/INR monitoring during and after concomitant use .
Mechanism Of Interaction
Unknown
Literature Reports
A) In a retrospective study (N=16), addition of linezolid to warfarin therapy for anticoagulation in patients using a left ventricular assist system for severe heart failure significantly reduced the mean warfarin dose from 3.23 mg/day (7 days prior to initiation of linezolid) to 2.69 mg/day (10 days after linezolid initiation). The mean PT/INR was increased, but the difference was nonsignificant. Linezolid was administered as 1200 mg/day for more than 7 days in 14 patients orally and in 2 patients intravenously .
B) In patients who had undergone heart surgery and were treated with warfarin to prevent postoperative thrombosis, addition of linezolid to treat heart-related infection significantly increased the PT/INR from 1.62 prior to addition of the antibiotic to 3 following 4 to 5 days of concomitant use (N=5). Over the course of the week following discontinuation of linezolid, the PT/INR was significantly decreased from 1.65 to 1.26 in 5 patients due to warfarin dosage adjustment or drug withdrawal. The mean duration of linezolid use was 27.3 days and the dose was 600 mg every 12 hours .
Linezolid Overview
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Linezolid is used to treat infections, including pneumonia, and infections of the skin . Linezolid is in a class of antibacterials called oxazolidinones. It works by stopping the growth of bacteria.
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Antibiotics such as linezolid will not work for colds, flu, and other viral infections. Using antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.
Warfarin Overview
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Warfarin is used to prevent blood clots from forming or growing larger in your blood and blood vessels. It is prescribed for people with certain types of irregular heartbeat, people with prosthetic (replacement or mechanical) heart valves, and people who have suffered a heart attack. Warfarin is also used to treat or prevent venous thrombosis (swelling and blood clot in a vein) and pulmonary embolism (a blood clot in the lung). Warfarin is in a class of medications called anticoagulants ('blood thinners'). It works by decreasing the clotting ability of the blood.
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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.