The use of specific antidotes as a response to bleeding complications during anticoagulant therapy for venous thromboembolism.

When a bleeding complication occurs during therapy with heparin or vitamin K antagonists, there is an option to give a specific antidote. Several new anticoagulants have been developed that are likely to have some risk of bleeding complications, for which no specific antidotes are available. Interestingly, it is unknown how often the use of an antidote is necessary in clinical practice. We investigated 1877 patients treated for venous thromboembolism included in three large clinical trials, of which 181 (9.6%) had a total of 225 adjudicated bleeding episodes; 46 hemorrhages being designated as major. Some form of antidote was given to 26 (14.4%) patients with a hemorrhage. Of the patients with at least one major hemorrhage, 19 (41.3%) received an antidote. Vitamin K was given to 23 (1.2%) patients, one (0.05%) patient received protamin sulfate and seven (0.4%) patients received fresh frozen plasma. The use of antidotes was comparable for initial and long-term treatment. Antidotes were statistically significantly more frequently given in Canada as compared to other participating countries. Vitamin K was more frequently given in case of a higher international normalized ratio value. Although antidotes against anticoagulant treatment are widely available, our analysis shows that in only a very small number of patients a direct, or slow-acting antidote to reverse the anticoagulant effect was used.