Incomplete reversal of enoxaparin toxicity by protamine: Implications of renal insufficiency, obesity, and low molecular weight heparin sulfate content

The use of low molecular weight heparin (LMWH) is increasing throughout North America and Europe for a number of reasons: 1) ease of use; 2) predictable dose response; 3) less heparin associated thrombocytopenia. However, aside from increased costs, LMWH has significant potential drawbacks: 1) poor reversibility; 2) tendency to accumulate in renal insufficiency; 3) less experience in subset patient groups such as morbid obesity. We report a case of a postoperative morbidly obese patient who developed enoxaparin toxicity secondary to acute renal failure that did not reverse with protamine sulfate infusion. In addition, we review the use of LMWH in renal insufficiency, dosing in obese patients, and the importance of sulfate content in the efficacy of protamine sulfate as a reversing agent for LMWH.