Inability to Achieve a Therapeutic INR Value While on Concurrent Warfarin and Rifampin

Krajewski, Kristin C.

doi:10.1177/0091270009353030

Cited by 26 publications

(37 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First of all, its use lacks a rationale: rifampicin has a place in the treatment of prosthetic joint infections only when combined with rigorous debridement and irrigation, and never when a fistula is present, the latter being by definition the case in VAD patients in the form of a driveline tunnel . Second, the use of rifampicin will interact with the coumarin anticoagulation therapy which VAD patients receive, potentially leading to life‐threatening dysregulations .…”

Section: Discussionmentioning

confidence: 99%

Therapy and Outcome of Staphylococcus aureus Infections of Intracorporeal Ventricular Assist Devices

et al. 2018

View full text Add to dashboard Cite

Infection of the driveline or pump pocket is a common complication in patients with ventricular assist devices (VADs) and Staphylococcus aureus is the main pathogen causing such infections. Limited evidence is currently available to guide the choice of antibiotic therapy and the duration of treatment in these patients. Patients at the University Medical Center Utrecht who developed a VAD‐related S. aureus infection between 2007 and 2016 were retrospectively assessed. Blood culture isolates were typed by whole genome sequencing to differentiate between relapses and reinfections, and to determine whether antibiotic therapy had led to acquisition of resistance mutations. Twenty‐eight patients had S. aureus VAD infections. Ten of these patients also suffered S. aureus bacteremia. Discontinuation of antibiotic therapy was followed by relapse in 50% of the patients without prior S. aureus bacteremia and in 80% of patients with bacteremia. Oral cephalexin could ultimately suppress the infection for the duration of follow‐up in 8/8 patients without S. aureus bacteremia and in 3/6 patients with S. aureus bacteremia. Clindamycin failed as suppressive therapy in 4/4 patients. Cephalexin appears an adequate choice for antibiotic suppression of VAD infections with methicillin‐susceptible S. aureus. In patients without systemic symptoms, it may be justified to attempt to stop therapy after treatment of the acute infection, but antibiotic suppression until heart transplant seems indicated in patients with S. aureus bacteremia.

show abstract

Section: Discussionmentioning

confidence: 99%

Therapy and Outcome of Staphylococcus aureus Infections of Intracorporeal Ventricular Assist Devices

et al. 2018

View full text Add to dashboard Cite

show abstract

“…A high INR predisposes patients to an increased risk of bleeding, while an INR below the therapeutic target indicates insufficient dose for prevention of thromboembolism. 2 Warfarin decreases blood coagulation by inhibiting vitamin K epoxide reductase, an enzyme that recycles oxidized vitamin K1 to reduced form produced during carboxylation of several blood coagulation proteins, mainly prothrombin and factor VII. Thus warfarin inhibits the vitamin Kdependent synthesis of biologically active forms of the clotting factors II, VII, IX and X, as well as the regulatory factors protein C and protein S. 3 Despite being labeled a vitamin K antagonist, warfarin does not antagonize the action of vitamin K1, but rather antagonizes vitamin K1 recycling, depleting active vitamin K1.…”

Section: Introductionmentioning

confidence: 99%

To achieve target international normalized ratio with concurrent warfarin and rifampicin therapy is a challenge: a case report and review of literature

Jha

2015

Int J Res Dermatol

View full text Add to dashboard Cite

<p>A 60-year-old man with a history of deep vein thrombosis put on anticoagulation therapy with warfarin 2 mg daily. Achieving a therapeutic level of anticoagulation was difficult despite escalating doses of warfarin, because of the interaction with rifampicin. A 5 to 6 fold increase in warfarin dose was prescribed to reach therapeutic international normalized ratios (INRs), but even these increases were insufficient to maintain his INR in the therapeutic range. After rifampicin was discontinued, warfarin doses were gradually reduced over the next 2 months. When concurrent warfarin-rifampicin therapy is necessary, vigilant monitoring of INR is imperative and rifampicin should be stopped. Warfarin is an oral anticoagulant used to get target INR to prevent thrombosis in various cardiovascular diseases. Its metabolism is affected by dugs, diet and individual characteristics. It is metabolized in liver by microsomal cytochrome P450 enzyme. Rifampicin is an essential component of first line antitubercular regimen. It induces enzyme P450, responsible for metabolism of warfarin. So to get target INR 2.5 to 3.5 is very difficult even with maximum possible dose of warfarin when patient taking simultaneously both drugs. In this case, rifampicin was stopped to achieve target INR. Tuberculosis patient on warfarin should not take rifampicin as component of first line antitubercular regimen.</p>

show abstract

“…Despite their benefits and widespread use, many challenges are faced when using warfarin. These include variable inter-patient warfarin dose response due to age, co-morbidities, liver function, albumin level, genetic polymorphism in enzymes, and numerous drug-drug/drug-diet interactions [1, 3–5]. Consequently, close monitoring using the international normalized ratio (INR) and patient specific dosing must be applied when utilizing warfarin [5].…”

Section: Introductionmentioning

confidence: 99%

“…Currently, only seven case reports have been published describing the interaction between warfarin and rifampicin, all of which come from the developed world where tuberculosis (TB) rates are much lower [5, 9–14]. Due to its efficacy and relative affordability, rifampicin is part of the first line regimen for treatment of TB [15].…”

Section: Introductionmentioning

confidence: 99%

“…Even though anticoagulation clinics have been shown to improve patient outcomes when compared to individual physician care, the limited data concerning this drug–drug interaction in this population presents an enormous challenge to clinicians providing care to patients on concomitant rifampicin and warfarin therapy [2]. Without data from patients receiving care in developing countries, clinicians have to rely primarily on the previously published case reports conducted only in developed countries, some of which suggest the need to increase warfarin doses by greater than 100–200 % [5, 9, 10]. …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Describing the Profile of Patients on Concurrent Rifampin and Warfarin Therapy in Western Kenya: A Case Series

et al. 2013

View full text Add to dashboard Cite

BackgroundRifampicin’s ability to induce hepatic enzymes is responsible for causing a clinically significant drug interaction with warfarin. Little data exists to guide clinicians on managing this interaction, especially in Sub-Saharan Africa where many patients are exposed to this combination due to a higher burden of tuberculosis.ObjectiveThe objective of the case series is to provide insight to practicing clinicians of the unique dynamics of this drug interaction in resource-constrained settings. The case series will provide details on commonly encountered scenarios and the dosage adjustments required to maintain a therapeutic INR.MethodsA retrospective chart review was conducted of patients attending the Moi Teaching and Referral Hospital anticoagulation clinic in Eldoret, Kenya. Patients were included if they had a history of concurrent rifampicin and warfarin therapy and a minimum follow up of 2 months. Descriptive statistics were used to explain the demographic characteristics, time to therapeutic INR and average weekly warfarin dose. The inference on proportions test was conducted to compare the time in the therapeutic range (TTR) for patients on concurrent rifampicin to the rest of the patients not receiving rifampicin in the clinic.ResultsOf the 350 patient charts evaluated, 10 met the inclusion criteria. The median percentage increase of the weekly warfarin dose from baseline was 15.7 %. For the patients in this analysis, the median TTR was 47 %.DiscussionPatients on concurrent therapy should be rigorously monitored with regular INR checks and warfarin dosage adjustments. Empiric dosage adjustments of warfarin should be avoided but patient characteristics can aid in understanding the alterations seen in INR.

show abstract

Inability to Achieve a Therapeutic INR Value While on Concurrent Warfarin and Rifampin

Cited by 26 publications

References 13 publications

Therapy and Outcome of Staphylococcus aureus Infections of Intracorporeal Ventricular Assist Devices

Therapy and Outcome of Staphylococcus aureus Infections of Intracorporeal Ventricular Assist Devices

To achieve target international normalized ratio with concurrent warfarin and rifampicin therapy is a challenge: a case report and review of literature

Describing the Profile of Patients on Concurrent Rifampin and Warfarin Therapy in Western Kenya: A Case Series

Contact Info

Product

Resources

About