HEPARIN-INDUCED THROMBOCYTOPENIA AND THROMBOSIS: A REVIEW OF PHARMACOLOGIC THERAPY
Nicole T Ansani

OBJECTIVESTo review pharmacological therapy in heparin-induced thrombocytopenia and thrombosis (HITT).

DATA SOURCES:Articles and abstracts in English published from 1966 to January 2000 were identified by MEDLINE and International Pharmaceutical Abstracts searches using the terms HIT, HITT, heparin-associated thrombocytopenia, thrombocytopenia, hirudin, lepirudin, argatroban, ancrod, heparinoids, orgaran, danaparoid, and org 10172. Additional articles were identified from the bibliographies of retrieved literature.

DATA SYNTHESIS:HITT is a devastating drug-induced immunologic complication that occurs in 2-5% of patients on heparin. Often, HITT results in life- or limb-threatening complications. HITT is frequently diagnosed by clinical presentation, and there is no optimal drug treatment approach. The first step of treatment is to discontinue all forms of heparin. If anticoagulation is indicated, several agents have been evaluated. Lepirudin, argatroban, and danaparoid are agents available for use in HITT. Lepirudin is a recombinant hirudin that directly complexes with thrombin. Danaparoid is a heparinoid moiety that works by inactivation factor Xa. Argatroban, a direct semisynthetic thrombin inhibitor, is the newest agent available. Ancrod is derived from pit viper venom and acts as a fibrinolytic agent; its use is not recommended. No studies have evaluated the comparative efficacy and safety of these agents.

CONCLUSIONS:Argatroban, danaparoid, and lepirudin have shown efficacy and safety in treatment of HITT. Each agent exerts differences in pharmacologic and pharmacokinetic parameters and has advantages and disadvantages in particular patient populations. Therapy must be guided on an individual basis. Further investigation is needed to ascertain an optimal treatment approach.

J Pharm Technol 2001;17:189-97.

ACPE Universal Program Number: 407-000-01-053-H01

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