Anticoagulants: therapeutics, risks, and toxicity--special emphasis on heparin-induced thrombocytopenia (HIT)

Anticoagulants are powerful and unavoidably dangerous drugs that must be carefully selected, monitored, and evaluated. Every patient undergoing treatment is at risk of excess bleeding, since the primary purpose of this class of drugs is to decrease clotting through a variety of biochemical and pharmacological mechanisms. Under the best of circumstances, significant numbers of patients (∼10%) experience toxicity on traditional warfarin oral anticoagulants. Beyond the obvious type A pharmacological toxicity, heparin products carry a seemingly paradoxical/novel risk of increased coagulopathy with limb- and life-threatening thromboembolic injuries (heparin-induced thrombocytopenia [HIT]). As a result of the great toxicity risk, many patients suffer injuries, and litigation is threatened or initiated, frequently against pharmacists and their employers. This article reviews the therapeutic use of old and novel anticoagulants, lists the types of litigation related thereto, and discusses the HIT risk associated with heparin products treatment. Litigation can result from adverse drug reactions and toxicity from anticoagulants.