Correlation of antifactor Xa concentrations with renal function in patients on enoxaparin

Enoxaparin is a low molecular weight heparin (LMWH) that has been shown to be effective in deep vein thrombosis, pulmonary embolism, and unstable angina. Because renal-function plays an important role in the clearance of LMWH, the authors sought to investigate the effect of renal function on enoxaparin. This prospective multiple-dose study evaluated 18 patients with varying degrees of renal function initiated on enoxaparin 1 mg/kg subcutaneously every 12 hours. Peak blood levels of anti-Xa concentrations were obtained 4 +/- 0.5 hours postdose after receiving at least three doses of enoxaparin. The median antifactor Xa levels were higher in patients with creatinine clearance (CLCr) less than or equal to 30 mL/min compared to CLCr greater than or equal to 31 mL/min (1.34 IU/ML vs. 0.91 IU/mL, respectively, p < 0.05). A linear correlation was established between creatinine clearance and anti-Xa concentrations (p < 0.0005). On the basis of the data, the authors believe that a dose adjustment is necessary in patients receiving repeated doses of enoxaparin with CLCr less than or equal to 30 mLlmin.