Outbreak of Adverse Reactions Associated with Contaminated Heparin

This epidemiologic report from the Centers for Disease Control and Prevention describes an outbreak of adverse reactions, occurring principally in dialysis units, that were caused by unfractionated heparin contaminated with oversulfated chondroitin sulfate. The identification of the contaminant and removal of the contaminated lots will end the outbreak, but it represents a serious breach in the safety of the U.S. drug supply. This epidemiologic report from the CDC describes an outbreak of adverse reactions, occurring principally in dialysis units, that were caused by unfractionated heparin contaminated with oversulfated chondroitin sulfate (OSCS). Unfractionated heparin is an anticoagulant medication that is used to prevent or treat thromboembolic disorders. Heparin is also commonly used to prevent clotting of extracorporeal blood during hemodialysis and cardiac surgery, as well as to maintain the patency of intravenous devices. Chemically, heparin is a heterogeneous mixture of sulfated polysaccharides; its main anticoagulant activity is mediated through activation of antithrombin. Commercially available heparin is derived from animal tissues; only porcine-derived heparin is approved for the U.S. market. Although heparin-induced thrombocytopenia is a well-described immune-mediated phenomenon among patients receiving heparin, immediate hypersensitivity reactions (e.g., exanthemas, bronchospasm, angioedema, and anaphylaxis) that are . . .