When is Clexane (enoxaparin) initiated in the ICU setting after patient admission?

Timing of Clexane (Enoxaparin) Initiation in ICU Patients

Clexane (enoxaparin) should be started within 24-36 hours of ICU admission for all patients without contraindications, with dosing based on renal function and weight. 1

General Recommendations for Clexane Initiation in ICU

• All hospitalized ICU patients should be considered for thromboprophylaxis with either unfractionated heparin (UFH) or low molecular weight heparin (LMWH) such as enoxaparin (Clexane) unless there are absolute contraindications 1
• For most ICU patients, Clexane should be initiated within the first 24-36 hours of admission 1
• In trauma patients specifically, Clexane should be started within 36 hours of injury 1
• For patients receiving spinal anesthesia, the first dose of Clexane should be delayed until after the epidural catheter has been removed; when this is not feasible, the catheter should be removed at least 8 hours after the last dose of LMWH 1

Dosing Considerations

Standard Dosing:

• For most ICU patients: Enoxaparin 40 mg subcutaneously once daily 1, 2
• For patients with obesity (BMI >30 kg/m²): Consider intermediate dosing of enoxaparin 40 mg twice daily 1
• For patients with morbid obesity (BMI >40 kg/m²): Consider enoxaparin 0.5 mg/kg twice daily 1

Renal Impairment Adjustments:

• For patients with creatinine clearance <30 mL/min: Enoxaparin 1 mg/kg subcutaneously once daily (instead of twice daily) 1
• Alternatively, for severe renal impairment: Consider using UFH instead of Clexane 1, 3

Age-Based Adjustments:

• For patients ≥75 years: 0.75 mg/kg subcutaneously every 12 hours without an initial IV bolus 1

Special Clinical Scenarios

Acute Coronary Syndromes:

• For NSTEMI patients managed with a planned conservative approach: Enoxaparin is a reasonable alternative to UFH 1
• For NSTEMI patients managed with a planned invasive approach: Either enoxaparin or UFH are reasonable choices 1
• For STEMI patients managed with fibrinolysis: Initial dose of 30 mg IV bolus followed by 1 mg/kg SC every 12 hours (first SC dose shortly after the IV bolus) 1

High Bleeding Risk Patients:

• For patients with increased bleeding risk but where anticoagulation is not contraindicated: Consider fondaparinux or bivalirudin as alternatives 1

Monitoring and Safety Considerations

• Major bleeding risk appears to be higher with enoxaparin compared to UFH in patients with renal impairment (OR: 1.84; 95% CI: 1.11-3.04) 3
• For patients with renal insufficiency, consider monitoring anti-Xa levels to guide dosing 4
• Avoid switching between enoxaparin and UFH due to increased risk of bleeding 1
• Concomitant use of medications that impair hemostasis (such as nonsteroidal anti-inflammatory drugs) should be avoided when possible 1

COVID-19 ICU Patients

• For COVID-19 patients in ICU, a "universal" thromboprophylactic strategy is recommended rather than an individualized VTE risk assessment approach 1
• Consider intermediate-dose regimens (enoxaparin 0.5 mg/kg twice daily or 40 mg twice daily) for COVID-19 ICU patients with elevated D-dimer (>6 times ULN) or high SIC score (≥4) 1

Common Pitfalls to Avoid

• Delaying thromboprophylaxis beyond 36 hours in ICU patients without clear contraindications 1
• Failing to adjust dosing for renal impairment, which can lead to increased bleeding risk 3, 4
• Switching between enoxaparin and UFH, which increases bleeding risk 1
• Not considering patient-specific factors such as obesity, which may require dose adjustments 1
• Administering LMWH too close to epidural catheter placement or removal (should maintain at least 8-hour interval) 1

Individualized dosing based on lean body weight and renal function has been shown to be superior to conventional dosing for achieving therapeutic anti-Xa concentrations in patients with renal impairment 4.