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

BMJ Case Rep. 2018 Feb 12:2018:bcr2016215155. doi: 10.1136/bcr-2016-215155.

Abstract

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.

Keywords: drug interactions; valvar diseases.

Publication types

  • Case Reports

MeSH terms

  • Anti-Bacterial Agents / adverse effects
  • Anti-Bacterial Agents / therapeutic use*
  • Anticoagulants / adverse effects
  • Anticoagulants / therapeutic use*
  • Aortic Valve Insufficiency / drug therapy*
  • Aortic Valve Insufficiency / surgery
  • Cytochrome P-450 Enzyme System
  • Drug Interactions
  • Endocarditis / drug therapy*
  • Female
  • Heart Valve Prosthesis Implantation*
  • Humans
  • International Normalized Ratio
  • Middle Aged
  • Phenprocoumon / adverse effects
  • Phenprocoumon / therapeutic use*
  • Rifampin / adverse effects
  • Rifampin / therapeutic use*
  • Treatment Outcome
  • Vitamin K / antagonists & inhibitors

Substances

  • Anti-Bacterial Agents
  • Anticoagulants
  • Vitamin K
  • Cytochrome P-450 Enzyme System
  • Phenprocoumon
  • Rifampin