What is the recommended dose of Enoxaparin (low molecular weight heparin) for a 50kg patient with Chronic Kidney Disease (CKD) on Hemodialysis (HD)?

Enoxaparin Dosing for CKD on Hemodialysis in a 50kg Patient

For a 50kg patient with end-stage renal disease on hemodialysis, use enoxaparin 30 mg subcutaneously once daily for prophylaxis or 50 mg (1 mg/kg) subcutaneously once daily for therapeutic anticoagulation, administered 6-8 hours after dialysis completion. 1, 2, 3

Critical Dosing Principles in Hemodialysis

Prophylactic Anticoagulation (DVT Prevention)

• Reduce to 30 mg subcutaneously once daily regardless of body weight when creatinine clearance is <30 mL/min or patient is on hemodialysis 1, 2
• This represents a 25% dose reduction from the standard 40 mg daily prophylactic dose 2
• The renal impairment takes absolute priority over weight-based adjustments for prophylaxis 1

Therapeutic Anticoagulation (DVT/PE Treatment)

• Use 1 mg/kg (50 mg for this 50kg patient) subcutaneously once daily instead of the standard twice-daily dosing 1, 2, 3
• This represents a 50% total daily dose reduction from standard therapeutic dosing 2
• Enoxaparin clearance is reduced by 44% in severe renal impairment, leading to drug accumulation 2, 3

Timing Relative to Dialysis

• Administer enoxaparin 6-8 hours after hemodialysis completion to minimize bleeding risk at the vascular access site 3
• The risk of major bleeding is highest at vascular access sites immediately post-dialysis if enoxaparin is given too close to the dialysis session 3
• For intradialytic anticoagulation during the dialysis session itself, a single bolus of 50-100 IU/kg (3,500-7,000 IU for 50kg patient) can be used 4

Bleeding Risk Without Dose Adjustment

• Patients with CrCl <30 mL/min have 2.25 times higher odds of major bleeding (OR 2.25,95% CI 1.19-4.27) with standard dosing 3, 5
• Unadjusted therapeutic dosing increases major bleeding risk nearly 4-fold (8.3% vs 2.4%; OR 3.88) 3
• The combination of underweight (<55 kg) and severe renal impairment represents dual high-risk factors for bleeding 3

Monitoring Recommendations

• Monitor anti-Xa levels in all hemodialysis patients receiving enoxaparin 1, 2, 3
• Check peak anti-Xa levels 4 hours after administration, only after 3-4 doses have been given 1, 3
• Target therapeutic anti-Xa range: 0.5-1.5 IU/mL for once-daily treatment dosing 1, 2
• Target prophylactic anti-Xa range: 0.29-0.34 IU/mL 1

Alternative Anticoagulation Strategy

• Unfractionated heparin (UFH) is the preferred alternative for therapeutic anticoagulation in hemodialysis patients, as it does not accumulate in end-stage renal disease 2, 3
• UFH dosing: 60 U/kg IV bolus (maximum 4000 U) followed by 12 U/kg/hour infusion (maximum 1000 U/hour), adjusted to maintain aPTT at 1.5-2.0 times control 2, 3
• Fondaparinux is absolutely contraindicated in patients with CrCl <30 mL/min 2, 3

Safety Evidence in Dialysis Patients

• A large retrospective study of 7,721 dialysis patients found that prophylactic-dose enoxaparin was not associated with increased serious bleeding compared to subcutaneous heparin (risk ratio 0.98; 95% CI 0.78-1.23) 6
• However, this safety profile applies only when appropriate dose reductions are implemented 6
• For intradialytic anticoagulation, a median dose of 70 IU/kg (3,500 IU for 50kg patient) was safe and effective in 24,117 hemodialysis treatments 4

Critical Caveats

• Never use standard twice-daily dosing (1 mg/kg every 12 hours) in hemodialysis patients due to exponential increase in bleeding risk 2, 3
• Do not switch between enoxaparin and unfractionated heparin mid-treatment, as this increases bleeding risk 1, 3
• Exercise extreme caution if the patient is elderly (≥70 years), as this represents an additional independent bleeding risk factor 3