Enoxaparin dosage adjustment in patients with severe renal failure: antifactor xa concentrations and safety.

STUDY OBJECTIVE

To evaluate the safety and efficacy, by measuring antifactor Xa levels, of enoxaparin 1 mg/kg subcutaneously once every 24 hours in patients with severe renal failure.

DESIGN

Prospective study.

SETTING

Emergency, internal medicine, geriatrics, and cardiology departments of a medical center in Israel.

PATIENTS

Nineteen patients with stage 4 or 5 chronic kidney disease who required full anticoagulation.

INTERVENTION

Patients received enoxaparin 1 mg/kg subcutaneously every 24 hours for 2 or more days, as determined by a treating physician.

MEASUREMENTS AND MAIN RESULTS

Data on patients' demographic and clinical characteristics were collected. Blood samples for peak and trough antifactor Xa levels were obtained during the enoxaparin treatment period. Of the 19 study patients, 14 (74%) had peak antifactor Xa levels within the recommended range for full anticoagulation of 0.5-1.0 U/ml after their first enoxaparin dose; no concentration exceeded 1.0 U/ml. The mean peak antifactor Xa level was not significantly different after the first enoxaparin dose compared with the second and third doses. The mean +/- SD trough antifactor Xa level, thought to be an indicator of drug accumulation, was 0.12 +/- 0.12 U/ml; its clinical significance and target range are still unknown. No major bleeding events were noted.

CONCLUSION

Enoxaparin 1 mg/kg once every 24 hours in patients with stage 4 or 5 chronic kidney disease who required full anticoagulation was safe, and this dose did not exceed recommended concentrations. The significance of enoxaparin trough levels remains unclear and should be investigated in future studies. Other dosing regimens of enoxaparin for specific patient populations should also be assessed for safety and efficacy.