ArticleThrombosis and haemostasis2019
The Effect of Flucloxacillin on Warfarin Anticoagulation: A Swedish Register-Based Nationwide Cohort Study.
Article in Thrombosis and haemostasis, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed, 7 citations in OpenAlex.
- Dicloxacillin is an inducer of intestinal P-glycoprotein but neither dicloxacillin nor flucloxacillin increases the risk of stroke/systemic embolism in direct oral anticoagulant users.British journal of clinical pharmacology · 2024Trial
- Warfarin and Antibiotics: Drug Interactions and Clinical Considerations.Life (Basel, Switzerland) · 2023Review
Corrections and comments
- Erratum issuedErratum.2019
Authors and funding
4 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundData indicate that codispensing flucloxacillin to patients already on warfarin may result in decreased warfarin efficacy.
objectivesThis article investigates the effect of flucloxacillin on warfarin anticoagulation. PATIENTS AND
methodsIn a retrospective cohort study of warfarin users, using three nationwide registers we included 5,848 patients receiving 10 days flucloxacillin treatment and 201 with ≥30 days treatment. To assess the potential for confounding by indication, we also identified 21,430 individuals initiating phenoxymethylpenicillin. International normalized ratio (INR) values and warfarin doses were calculated day-by-day and proportion of patients with a subtherapeutic INR week-by-week during cotreatment.
resultsFollowing initiation of flucloxacillin with a planned treatment duration of 10 days and ≥30 days, the mean INR decreased from 2.36 (95% confidence interval [CI] 2.34; 2.37) to 2.20 (95% CI 2.19; 2.21) and from 2.24 (95% CI 2.16; 2.32) to 1.96 (95% CI 1.89; 2.02), respectively. Consequently, for individuals with 10 days treatment the proportion of patients with a subtherapeutic INR of < 2 increased from 22% in the week preceding flucloxacillin initiation to 35% in the third week after initiation of flucloxacillin. In patients with 30 days treatment, the proportion increased from 34 to 63% by week 6. In individuals initiating phenoxymethylpenicillin, INR levels did not decrease.
conclusionOne in three patients with 10 days flucloxacillin and almost two in three patients initiating long-term treatment, was exposed to a subsequent subtherapeutic anticoagulant effect. To avoid unnecessary thromboembolic complications, the initiation of flucloxacillin should be accompanied by closer INR monitoring which may be especially important among individuals with lengthy treatments.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.