Warfarin with Ceftriaxone Interaction Details


Brand Names Associated with Warfarin

  • Coumadin®
  • Jantoven®
  • Warfarin

Brand Names Associated with Ceftriaxone

  • Ceftriaxone Injection
  • Rocephin®

Medical Content Editor
Last updated Nov 07, 2023


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Interaction Effect

An increased risk of bleeding


Interaction Summary

A case report described significant elevations in INR on two occasions following administration of ceftriaxone in a 67-year-old woman receiving long-term, stable warfarin therapy. More frequent INR monitoring is recommended when initiating, discontinuing, or changing doses of antibiotics, even if the treatment duration is short-term .


Severity

Moderate


Onset

Unspecified


Evidence

Probable


How To Manage Interaction

Concomitant use of ceftriaxone and warfarin may result in significant elevations in INR as evidence in a case report. More frequent INR monitoring is recommended when initiating, discontinuing, or changing doses of antibiotics, even if the treatment duration is short-term 


Mechanism Of Interaction

Unknown


Literature Reports

A) A 67-year-old Native American Indian woman, stabilized on warfarin, had significantly elevated INR levels 4 days after ceftriaxone administration. She had been on stable warfarin therapy for 8 years (INR goal, 2.5 to 3.5), and 4 to 5 weeks prior to receiving ceftriaxone, her INR levels were stable (INR, 1.9 to 3) with warfarin 52.5 to 54.5 mg weekly. Four days after receiving IM ceftriaxone 1 g for UTI, she presented with an INR was 10.74 compared with an INR of 3 the previous week. Although her current therapy included concomitant medications for comorbid conditions (diabetes mellitus type 2, COPD, dyslipidemia, GERD, and depression), she denied any changes to her medications or diet. Subsequently, the next warfarin dose was held and she received phytonadione 5 mg. The following day, her INR decreased to within goal range (INR, 3.4) and stabilized over the next 4 to 5 weeks at a warfarin weekly dose of 54.5 to 55.5 mg. About 2 months later, she received a second dose for UTI plus cefuroxime axetil 500 mg twice daily for 7 days and phenazopyridine 200 mg 3 times daily as needed. Again, 4 days later, her INR increased to 16.99. Her warfarin dose was held for 2 days, and she received phytonadione 5 mg. Subsequently, she resumed warfarin 7.5 mg daily and her INR reached her goal range .

Warfarin Overview

  • 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.

See More information Regarding Warfarin

Ceftriaxone Overview

  • Ceftriaxone injection is used to treat certain infections caused by bacteria such as gonorrhea (a sexually transmitted disease), pelvic inflammatory disease (infection of the female reproductive organs that may cause infertility), meningitis (infection of the membranes that surround the brain and spinal cord), and infections of the lungs, ears, skin, urinary tract, blood, bones, joints, and abdomen. Ceftriaxone injection is also sometimes given before certain types of surgery to prevent infections that may develop after the operation. Ceftriaxone injection is in a class of medications called cephalosporin antibiotics. It works by killing bacteria.

  • Antibiotics such as ceftriaxone injection will not work for colds, flu, or other viral infections.Using antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

See More information Regarding Ceftriaxone Injection

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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.