Efficacy and Safety of New Direct Oral Anticoagulants for The Treatment of Venous Thromboembolism

Abstract

Direct oral anticoagulants (DOAC) are oral anticoagulants that act by directly inhibiting specific coagulation factors. This drug class was developed to overcome the limitation of warfarin that requires routine monitoring of international normalized ratio. One of the main indications of DOAC is for the treatment of venous thromboembolism (VTE) caused by abnormalities of blood coagulation, declined blood flow, or damaged blood vessel epithelial cells, and VTE can be divided into two types: deep vein thrombosis, and pulmonary embolism (PE). Time to maximum concentration of DOAC in blood ranges from 1 to 6 hours. The drug is metabolized in liver, and excreted in urine and feces. Adverse effects of DOAC such as major bleeding must be closely monitored. Renal function should also be evaluated as doses of DOAC must be adjusted in renal failure. Comparison of efficacy and safety of DOAC in the treatment of VTE suggested that DOAC can reduce VTE recurrence, major bleeding, and clinically relevant non-major bleeding, although these effects were not different from warfarin. On considering the effect of specific DOAC, it was found that apixaban and rivaroxaban can reduce the risk of major bleeding. DOAC that have been approved to be used in Thailand are apixaban, dabigatran, edoxaban, and rivaroxaban, which are all categorized as non-essential drugs in the national drugs lists. Thai practice guideline for VTE has recommended heparin and warfarin as the first line treatment, without inclusion of other DOAC.