Comparative study of the stability of oral anticoagulant therapy using phenprocoumon or warfarin.


Phase N/A Results N/A

Trial Description

Long acting coumarin derivatives can reach a more stable anticoagulant effect. Short acting coumarins are more easy to adjust. The half-life of warfarin lies between the half-life of acenocoumarol and phenprocoumon and can thereby possibly have the advantage of long acting coumarins as well as the advantage of short acting coumarins.


  • Warfarin (Coumadin┬«)Drug
    Intervention Desc: Anticoagulant (Vitamin K antagonist)
  • Phenprocoumon (Marcoumar, Marcumar and Falithrom))Drug
    Intervention Desc: Phenprocoumon is an anticoagulant drug, a derivative of coumarin. It is a vitamin K antagonist that inhibits coagulation by blocking synthesis of coagulation factors II, VII, IX and X. It is used for the prophylaxis and treatment of thromboembolic disorders (thrombosis/pulmonary embolism).

Trial Design

Randomised, active controlled, parallel group trial.

Patient Involvement

Patients were randomized to either Treatment group: oral anticoagulant treatment with warfarin or Control group: oral anticoagulant treatment with phenprocoumon. Patients INR is followed while on treatment and they are monitored for bleeding and thrombotic complications.


Type Measure Time Frame Safety Issue
Primary Time spent within therapeutic range, time to the first international normalised ratio (INR) in range, percentage of INRs above range after initiation scheme, reaction of INR to interruption of coumarin or vitamin K administration.
Secondary 1. Bleeding complications 2. Thrombotic complications


Leiden University Medical Centre