Potential coagulation effects of preoperative complementary and alternative medicines.

Complementary and alternative medicines (CAM) are commonly consumed by patients before surgery, though CAM use seldom is revealed during preoperative assessment. Many alternative medicines may interact with anesthetic drugs to inhibit coagulation, precipitating unnecessary surgical blood loss. This article reviews research of herbs and dietary supplements that have effects on the coagulation process. Knowledge of specific pharmacodynamic mechanisms of action is essential to determine herbs and dietary supplements that may interact with drugs that alter the hemostatic process. Further integrative research, education of practitioners, and greater patient communication are necessary to prevent herb-supplement drug interactions that may inhibit coagulation in surgical patients.