Excessive anticoagulation in patients with mild renal insufficiency receiving long-term therapeutic enoxaparin

Low-molecular-weight heparins, such as enoxaparin, are increasingly being used for treatment of venous thromboembolism. We describe two patients who received therapeutic enoxaparin for several months. Although their serum creatinine values were normal, both had mild renal insufficiency (creatinine clearance 60-70 ml/min), and both accumulated the drug abnormally and experienced clinical bleeding. These results suggest that patients receiving enoxaparin (or other low-molecular-weight heparins) in therapeutic doses for periods of more than 4 weeks should be considered for laboratory monitoring to avoid bleeding.