The dosage of the subcutaneous low molecular weight heparin enoxaparin in unstable angina patients undergoing coronary angiogram and coronary angioplasty depends clearly on the renal function. It should be significantly reduced to 64% of the standard dose (1 mg/kg per 12 h) in patients with severe renal failure (creatinine clearance<30 ml/min) to provide a safe anticoagulant profile.