What is the recommended dose of enoxaparin (low molecular weight heparin) for a 130kg patient with pulmonary embolism and lung infarct?

Enoxaparin Dosing for 130kg Patient with Pulmonary Embolism and Lung Infarct

For a 130kg patient with pulmonary embolism and lung infarct, administer enoxaparin 1 mg/kg subcutaneously every 12 hours (130 mg twice daily), which translates to 130 mg SC every 12 hours. 1

Standard Therapeutic Dosing

• The recommended dose is 1 mg/kg subcutaneously every 12 hours, which for this 130kg patient equals 130 mg twice daily 1, 2
• An alternative FDA-approved regimen is 1.5 mg/kg once daily (195 mg once daily for this patient), though this is primarily approved for inpatient use and has shown higher rates of recurrent PE and bleeding in cancer patients 1, 3

Critical Consideration: Dose Capping in Obesity

Do not "dose cap" at 100kg for this patient. While dose capping is commonly practiced to minimize bleeding risk, it results in under-dosing and increases the risk of recurrent thromboembolism 4

• For patients weighing 120-139 kg, dosing at 0.75-0.85 mg/kg produces therapeutic anti-Xa levels in 62% of patients, with 14% sub-therapeutic and 24% supra-therapeutic 4
• At 130kg, this patient falls into the weight range where 1 mg/kg dosing (130 mg twice daily) is appropriate 4
• Monitor anti-Xa levels in this obese patient due to high inter-patient variability, with target peak levels of 0.5-1.0 IU/mL drawn 4 hours after the third dose 4

Duration and Bridging Strategy

• Continue enoxaparin for minimum 5 days regardless of INR response 1
• If bridging to warfarin, start warfarin on day 1 and continue enoxaparin until INR is 2.0-3.0 for 2 consecutive days 1
• Do not discontinue enoxaparin before both criteria are met (minimum 5 days AND therapeutic INR × 2 days) 1

Alternative: Direct Oral Anticoagulants

• Rivaroxaban 15 mg twice daily for 21 days, then 20 mg once daily eliminates the need for enoxaparin bridging entirely and reduces major bleeding by 50% compared to enoxaparin/warfarin 1
• Apixaban can be started immediately without enoxaparin lead-in, while dabigatran and edoxaban require ≥5 days of enoxaparin before switching 1

Renal Function Assessment

• Check creatinine clearance immediately - if CrCl <30 mL/min, reduce enoxaparin to 1 mg/kg once daily (130 mg once daily) due to 44% reduction in renal clearance and 2-3 fold increased bleeding risk 1
• For severe renal impairment, consider unfractionated heparin with aPTT monitoring as an alternative 1

Monitoring Requirements

• Monitor platelet count every 2-3 days from day 4 to day 14 to screen for heparin-induced thrombocytopenia 1
• Given the patient's weight of 130kg, obtain anti-Xa levels to confirm therapeutic anticoagulation 4

Common Pitfalls to Avoid

• Never stop enoxaparin before day 5, even if INR becomes therapeutic earlier 1
• Never dose cap at 100kg in the absence of renal impairment, as this leads to sub-therapeutic anticoagulation 4
• Never use once-daily dosing (1.5 mg/kg) for outpatient treatment, as it shows higher recurrence and bleeding rates compared to twice-daily dosing 3