BMJ Case Reports 2018; doi:10.1136/bcr-2016-215155
  • Reminder of important clinical lesson

Problems in anticoagulation of a patient with antibiotic treatment for endocarditis: interaction of rifampicin and vitamin K antagonists

  1. Martin Steeg1
  1. 1Klinik für Kardiologie und Kreislauferkrankungen, Universitätsklinikum Tübingen, Tuebingen, Germany
  2. 2Department fur Experimentelle und Klinische Pharmakologie und Toxikologie, Eberhard Karls Universitat Tubingen, Tübingen, Germany
  1. Correspondence to Professor Tobias Geisler, tobias.geisler{at}
  • Accepted 25 January 2018
  • Published 12 February 2018


The cytochrome P450 is a superfamily of isoenzymes that are responsible for the metabolism of many drugs. Significant changes in pharmacokinetics and drug interactions may be due to induction of hepatic cytochrome P450 enzymes. Rifampicin is a common inducer of CYP3A4. We report a case of a 57-year-old woman who was suspected for endocarditis and therefore treated with rifampicin. Due to previous mechanical aortic valve replacement, she also received phenprocoumon for anticoagulation. Although continuing anticoagulant therapy, antibiotic coadministration led to normal international normalised ratio (INR) level. Fifteen days after the treatment with rifampicin ended, INR returned to therapeutic level.


  • Contributors LM and KM had the idea for the article. LM performed the literature search, wrote the article and is the guarantor. MS, MG and TG revised the publication.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Register for free content

The full text of all Editor's Choice articles and summaries of every article are free without registration

The full text of Images in ... articles are free to registered users

Only fellows can access the full text of case reports (apart from Editor's Choice) - become a fellow today, or encourage your institution to, so that together we can grow and develop this resource

Don't forget to sign up for content alerts so you keep up to date with all the case reports as they are published, and let us know what you think by commenting on the Editor's blog

Navigate This Article