Antithrombotic effects of Danggui, Honghua and potential drug interaction with clopidogrel.

AIM OF THE STUDY: The antithrombotic effect of Danggui and Honghua, herbs commonly used in Traditional Chinese medicine to treat the syndrome corresponding to vascular thrombosis, and their potential interactions with clopidogrel were investigated.
MATERIALS AND METHODS: The efficacy of Danggui, Honghua alone or combination with clopidogrel was determined in three experimental models. Bleeding time and hematology parameters were measured to evaluate safety.
RESULTS: Danggui and Honghua exhibited antithrombotic effects against venous thrombosis and pulmonary embolism. Especially in the case of venous thrombosis, the thrombus weight was decreased significantly by Danggui or Honghua when compared with control. Bleeding time and coagulation time tended to be prolonged by Danggui or Honghua, but only prothrombin time (PT) and thrombin time (TT) were augmented significantly. The combinations of Danggui plus clopidogrel and of Honghua plus clopidogrel failed to significantly enhance the antithrombotic effects of clopidogrel alone against arterial thrombosis, venous thrombosis and pulmonary embolism. However, both Danggui and Honghua significantly potentiated the prolongation caused by clopidogrel on the tail bleeding time and PT.
CONCLUSIONS: Danggui and Honghua possess antithrombotic activity and cannot potentiate the antithrombotic effect of clopidogrel. However, they significantly enhance the deleterious effect of clopidogrel on bleeding time, PT and TT. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.