From the Guidelines
For patients on hemodialysis requiring Lovenox (enoxaparin), the recommended dose is 1 mg/kg once daily, which is a 50% reduction from the standard twice-daily dosing used in patients with normal renal function. This dose reduction is necessary because enoxaparin is primarily eliminated by the kidneys, and patients with severe renal impairment have decreased clearance, leading to drug accumulation and increased bleeding risk 1.
Key Considerations
- For acute coronary syndrome or venous thromboembolism treatment in hemodialysis patients, this reduced dosing is appropriate.
- If using Lovenox for dialysis circuit anticoagulation, a dose of 0.5-1 mg/kg into the arterial line at the start of dialysis may be used.
- Anti-Xa level monitoring is strongly recommended when using Lovenox in hemodialysis patients, with target levels of 0.5-1.0 IU/mL for therapeutic anticoagulation, measured 4 hours after administration.
Monitoring and Alternatives
- Patients should be monitored closely for signs of bleeding, and consideration should be given to alternative anticoagulants like unfractionated heparin in patients at very high bleeding risk, as it has non-renal clearance and can be more easily reversed 1.
- The risk of bleeding is also increased when patients with severe renal failure are treated with UFH, so the problem may be the renal function rather than the dosing regimen 1.
Evidence Summary
- A meta-analysis of 18 observational studies or subgroup analyses of studies using therapeutic doses of LMWH provides some indirect evidence on this patient population, suggesting that standard doses of LMWH led to higher peak levels of anti-factor Xa in patients with a creatinine clearance < 30 mL/min compared with those with a creatinine clearance > 30 mL/min 1.
- The ESSENCE trial showed that enoxaparin therapy reduced the rates of recurrent ischemic events and invasive diagnostic and therapeutic procedures in patients with UA or non–Q-wave MI 1.
From the Research
Lovenox Renal Dose Hemodialysis
- The dosage of Lovenox (enoxaparin) for patients undergoing hemodialysis is a critical consideration to prevent thrombosis and bleeding complications.
- A study from 2 found that weight-unadjusted enoxaparin in patients with acute renal failure in continuous venovenous hemodialysis was associated with an increased rate of bleeding, highlighting the need to adjust the drug dose and monitor anti-factor Xa activity during dialysis.
- According to 3, enoxaparin should be adjusted to 50-65% of the original dose for patients with a creatinine clearance of <30 ml/min and 30-60 ml/min, respectively, to minimize the risk of bleeding.
Monitoring Anti-Xa Levels
- The study from 3 also suggests that trough concentration anti-Xa monitoring is preferred over peak monitoring, aiming at a maximum concentration of 0.4 IU/mL for once-daily dosed tinzaparin and 0.5 IU/mL for twice-daily dosed enoxaparin and nadroparin.
- However, a study from 4 found that anti-Xa activity levels did not correlate with the percentages of open fibers in the dialyzers, questioning the usefulness of monitoring anti-Xa levels to predict fiber patency.
- Another study from 5 found that plasma enoxaparin fragments remained detectable and relatively unchanged throughout dialysis, while therapeutic anti-Xa levels quickly dropped, suggesting that anti-Xa activity may not be a reliable surrogate measure for effective anticoagulation.
Therapeutic Anticoagulation
- A retrospective chart review from 6 compared the safety and efficacy of enoxaparin versus unfractionated heparin for therapeutic anticoagulation in hemodialysis patients, finding no significant difference in major bleeding or thromboembolism between the two groups.
- The study from 6 used an average daily dose of enoxaparin of 0.7±0.2mg/kg/day to target therapeutic levels, with a range of 0.4-1mg/kg/day, and found that hospital length of stay was shorter in the enoxaparin group.