Inadvertent Overdose of Low-Molecular-Weight Heparin in an Elderly Patient with Deep Vein Thrombosis and Acute Kidney Injury.

Low-molecular-weight heparin (LMWH) is commonly used to treat deep vein thrombosis. The dose is usually based on the patient’s body weight, and for some preparations the manufacturer recommends a daily maximum dose. Unlike the situation for unfractionated heparin, no effective antidote is available for LMWH overdose. Protamine sulphate neutralizes the anticoagulant effect of unfractionated heparin, but it is only partially effective against LMWH. Protamine sulphate is composed of polypeptides that bind heparin to form a stable, inactive complex that inhibits the anti–factor IIa effect of LMWH,1 but the effect on anti–factor Xa is only partial,2,3 reaching up to 74%.4 Despite the frequent use of LMWH, there are few descriptions of management strategies for LMWH overdoses. Furthermore, most case reports of LMWH overdose have involved patients who were relatively young.1-3,5-7 To the authors’ knowledge, the current article is the first report of LMWH overdose in a patient over 80 years of age.