Dalteparin Ampules, Prefilled Syringes, and Single-Dose Vials and Thrombocytopenia

The use of heparin is contraindicated in patients with severe thrombocytopenia. Acute thrombocytopenia can occur in patients receiving heparin, with a reported incidence of up to 30%. Platelet counts should be obtained before and periodically during heparin administration, including regular and repeated use of heparin flush solutions if given for longer than 5 days. Mild thrombocytopenia with counts above 100,000/mm3 may remain stable or reverse despite continued heparin administration. However, thrombocytopenia of any degree should be closely monitored. Therapy should be discontinued if the count falls below 100,000/mm3 or if recurrent thrombosis develops, and an alternative, nonheparin anticoagulant (e.g., argatroban, bivalirudin, lepirudin) administered if necessary. Heparin-induced thrombocytopenia (HIT) is a serious antibody-mediated reaction resulting from irreversible aggregation of platelets. HIT may progress to the development of venous and arterial thromboses, a condition referred to as heparin-induced thrombocytopenia and thrombosis (HITT). Thrombotic events may also be the initial presentation for HITT, and may include deep vein thrombosis, pulmonary embolism, cerebral vein thrombosis, limb ischemia, stroke, myocardial infarction, mesenteric thrombosis, renal artery thrombosis, skin necrosis, gangrene of the extremities that may lead to amputation, and possibly death. Both HIT and HITT can occur up to several weeks after the discontinuation of heparin therapy. Patients presenting with thrombocytopenia or thrombosis after discontinuation of heparin should be evaluated for HIT and HITT. Following an episode, any future use of heparin should be avoided, and use of low-molecular weight heparin should consider the potential for cross-reactivity with the HIT antibody and approached with extreme caution, if not otherwise contraindicated.