Oral anticoagulation with
vitamin-K-antagonists is very effective in
secondary prevention of
venous thromboembolism. In Germany, most commonly
Phenprocoumon is used, while most of the evidence-based data are available for
Warfarin. The initial treatment of acute
venous thromboembolism requires immediate anticoagulation with
heparin and a subsequent overlapping treatment with oral
anticoagulants. During this phase, anticoagulation may be unstable with increased risk for
bleeding. An INR target range between 2 and 3 provides effective protection with minimal risk for major
bleeding. The individual risk for
bleeding may be estimated by a clinical score. Six months of oral anticoagulation is the standard duration for a first episode of
venous thromboembolism, while recurrencies are treated for at least one to two years. The duration may be tailored to the individual patient according to underlying risk factors for recurrencies and for
bleeding. Because of a plethora of practical problems and the narrow therapeutic window, there is a need for new
antithrombotic agents. These may allow a longer duration of
secondary prevention with improved protection against recurrencies without sacrificing safety.