Maximum Dose of Enoxaparin (Lovenox)
The maximum single dose of enoxaparin varies by indication: for prophylaxis, the first two subcutaneous doses should not exceed 100 mg in patients <75 years receiving fibrinolytic therapy, and 75 mg in patients ≥75 years; for therapeutic anticoagulation, there is no absolute maximum dose, but weight-based dosing of 1 mg/kg every 12 hours or 1.5 mg/kg once daily is standard, with dose caps applied in specific clinical contexts.
Context-Specific Maximum Dosing
Prophylactic Dosing
- Standard prophylactic enoxaparin is 40 mg subcutaneously once daily for most hospitalized medical and surgical patients 1, 2
- In patients with severe renal impairment (CrCl <30 mL/min), the maximum prophylactic dose is reduced to 30 mg once daily to prevent drug accumulation and 2–3-fold increased bleeding risk 1, 3, 2
- For obese patients (BMI ≥40 kg/m²), intermediate prophylactic dosing of 40 mg every 12 hours may be used, but this represents the upper limit for prophylaxis 1
Therapeutic Dosing in Acute Coronary Syndromes
- In patients <75 years receiving fibrinolytic therapy, enoxaparin dosing is 30 mg IV bolus followed by 1 mg/kg subcutaneously every 12 hours, with the first two subcutaneous doses capped at 100 mg each 4
- In patients ≥75 years receiving fibrinolytic therapy, the IV bolus is omitted and dosing is reduced to 0.75 mg/kg subcutaneously every 12 hours with a maximum of 75 mg for the first two doses 4, 1
- For primary PCI, enoxaparin is given as a single 0.5 mg/kg IV bolus with no specified maximum 4
Therapeutic Dosing for Venous Thromboembolism
- Standard therapeutic regimens are 1 mg/kg subcutaneously every 12 hours or 1.5 mg/kg once daily with no absolute maximum dose in patients with normal renal function 4, 1, 5
- In severe renal impairment (CrCl <30 mL/min), therapeutic dosing is reduced to 1 mg/kg once daily (a 50% reduction in total daily dose) 1, 3, 2
- For patients with BMI ≥40 kg/m², dose-adjusted regimens use 0.8 mg/kg every 12 hours rather than standard 1 mg/kg dosing 1
Critical Dose-Capping Rationale
Why Dose Caps Exist in Specific Populations
Elderly patients receiving fibrinolysis: The 75 mg cap for patients ≥75 years reflects the substantially higher bleeding risk in this population, where standard dosing would lead to excessive anticoagulation 4, 1
Renal impairment: Enoxaparin clearance decreases by 31% in moderate renal impairment (CrCl 30–60 mL/min) and 44% in severe renal impairment (CrCl <30 mL/min), resulting in drug accumulation and 2–3-fold increased major bleeding risk without dose reduction 1, 3, 2
Obesity considerations: While there is no absolute maximum dose for obese patients, weight-based dosing in extreme obesity may require anti-Xa monitoring to ensure appropriate anticoagulation without excessive bleeding 1
Monitoring and Safety Thresholds
- Anti-Xa monitoring is recommended in patients with severe renal impairment (CrCl <30 mL/min) receiving prolonged therapy, targeting 0.5–1.5 IU/mL measured 4–6 hours after the dose, after 3–4 consecutive doses 1, 3, 2
- For prophylactic dosing, target anti-Xa levels are 0.2–0.5 IU/mL 1
- For therapeutic twice-daily dosing, target anti-Xa levels are 0.5–1.0 IU/mL 1, 3
- For therapeutic once-daily dosing, target peak anti-Xa levels are 1.0–1.5 IU/mL 1
Common Pitfalls Regarding Maximum Dosing
Failure to cap doses in elderly patients with STEMI: Using standard 1 mg/kg dosing (up to 100 mg) in patients ≥75 years receiving fibrinolysis dramatically increases intracranial hemorrhage risk; the 75 mg cap is mandatory 4, 1
Not reducing doses in renal impairment: The most frequent dosing error is using standard prophylactic (40 mg daily) or therapeutic (1 mg/kg every 12 hours) dosing in patients with CrCl <30 mL/min, leading to dangerous drug accumulation 1, 3, 2
Assuming a universal maximum exists: Unlike some medications, enoxaparin does not have a single "maximum dose"—the ceiling varies by indication, patient age, renal function, and body weight 4, 1
Overlooking the 100 mg cap in fibrinolysis protocols: Even in younger patients (<75 years) with normal renal function receiving fibrinolytic therapy for STEMI, the first two subcutaneous doses are capped at 100 mg each to balance efficacy and bleeding risk 4