Which of the following drugs is recommended for the treatment of Heparin Induced thrombocytopenia
Answer is B (Lepirudin) Lepirudin (direct thrombin inhibitor) is a recommended agent for Heparin induced thrombocytopenia and thrombosis. Currently Recommended Agents for Heparin Induced Thrombocytopenia Lepirudin (Direct Thrombin Inhibitor) Argatroban (Direct Thrombin Inhibitor) Danaparoid (Mixture of Non Heparin Glycosaminoglycans) Bivalirudin (Direct thrombin inhibitor) is under evaluation for HIT Heparin Induced Thrombocytopenia (HIT) Heparin Induced Thrombocytopenia is an impoant complication / adverse effect of Heparin administration that necessitates use of alternative agents to treat or prevent thrombus formation HIT is usually seen as a complication of the use of unfractionated heparin but may also be seen with the use of LMWH HIT may be non immune mediated (Type I, Mild) or immune mediated due to development of antibodies (Type 2/ Significant) Type I Non immune mediated Benign Mild Thrombocytopenia Heparin Therapy may be continued Type II Immune mediated Severe Significant thrombocytopenia Heparin must be discontinued immediately Heparin Induced thrombocytopenia Type II is a serious form of HIT that can result in serious complications The diagnosis of Immune mediated HIT depends on clinical criteria with confirmation by specific laboratory tests Clinical Criteria for Immune Mediated (Type II) HIT Thrombocytopenia < 150, 000/111 or a 50% decrease from pretreatment values Thrombocytopenia follows heparin exposure by at least 5 days (Time taken to form antibodies) Reasonable exclusion of other clinical causes of thrombocytopenia Onset of new thrombotic event or extension of previous thrombosis Management of HIT (Immune mediated) Direct Thrombin Inhibitors Lepirudin and Argobatran along with Danaparoid are the recommended alternative anticoagulants for patients with Heparin Induced thrombocytopenia. Direct thrombin inhibitors (Lepirudin and Argobatram) are usually preferred but all three drugs are effective anticoagulants and the choice of drug depends on personal experience and patient characteristics like hepatic or renal insufficiency and desired route of administration Heparin administration should be stopped immediately. Low Molecular Weight Heparin (LMWH) should not be substituted because it may cross react with and-heparin antibodies Warfarin should not be used until the thrombocytopenia is resolved and the patient is adequately anticoagulated with another agent. Warfarin may precipitate venous limb gangrene or multicentric skin necrosis in patients with HIT Comparison of Danaproid, Lepirudin, and Argatroban for the treatment of Heparin induced Thrombocytopenia Danaproid Lepirudin Aragtroban Mechanism of action Primarily inhibits Xa in a complex with Antithrombin III Directly inhibits thrombin Directly inhibits thrombin Administration IV or SC IV IV Half-life 24 hours 13 hours 30 minutes Reversible No No No Monitoring Anti-Xa activity using a danaproid standard aPTT aPTT Use in pregnancy Several repoed cases No repoed experience .No repoed experience Dose adjustment for renal failure Yes, monitor Xa activity dosely in patients with renal insufficiency Yes, monitor Xa activity closely in patients with renal insufficiency No Special considerations Cross- reacts with heparin-induced antibodies in some cases Antibodies may develop to lepirudin and prolong the half -life All three drugs are anticoagulant in patients with heparin-induced thrombocytopenia. The choice of drug depends on personal experience and patient characteristics such as renal or hepatic insufficiency, desired route of administration.
Abciximab
Lepirudin
Warfarin
Alteplase