Pharmacotherapy Newsletter

Volume 1, Issue 25, 07/06/2009

Question

What is the difference between heparin associated thrombocytopenia (HAT) and heparin induced thrombocytopenia (HIT)?

Answer

This is part 2 of a 4 part series related to heparin induced thrombocytopenia (HIT).  The mechanism for how heparin based medications can cause reductions in platelet counts, as well as the formation of a potentially life-threatening thrombus, was covered in detail in part 1.¹  Now that the mechanism for this adverse event is known, it is important for clinicians to recognize the various categories of thrombocytopenia while on heparin based medications.  This is relevant since not all forms of thrombocytopenia with heparin based products are considered life-threatening or result in thrombus formation.