What is the recommended dose of Lovenox (enoxaparin) for superficial thrombophlebitis?

Lovenox Dosing for Superficial Thrombophlebitis

For superficial thrombophlebitis of the lower extremity ≥5 cm in length, use prophylactic-dose enoxaparin 40 mg subcutaneously once daily for 45 days. 1

Recommended Dosing Regimen

• Enoxaparin 40 mg subcutaneously once daily for 45 days is the recommended dose for superficial vein thrombosis (SVT) of at least 5 cm in length 1
• This prophylactic dose has been shown to significantly reduce the risk of venous thromboembolism (VTE) and superficial thrombophlebitis extension 2
• The 2012 ACCP guidelines specifically recommend prophylactic-dose fondaparinux or LMWH for 45 days over no anticoagulation (Grade 2B recommendation) 1

Evidence Supporting This Approach

• In clinical trials, enoxaparin 40 mg once daily reduced the combined incidence of deep and superficial venous thromboembolism from 30.6% in placebo to 8.3% (P<.001) 2
• The risk of progression to deep vein thrombosis is approximately 3.6% without treatment, which can be reduced to less than 1% with prophylactic-dose enoxaparin 2
• Treatment duration of 45 days is based on the natural history of superficial thrombophlebitis and risk of late complications 1

Alternative Considerations

While fondaparinux 2.5 mg daily is suggested as preferred over LMWH in the ACCP guidelines (Grade 2C), enoxaparin remains a highly effective and more widely available alternative 1. The choice between fondaparinux and enoxaparin is weak, and enoxaparin 40 mg daily is well-established in clinical practice 1.

Dose Adjustments for Special Populations

• Severe renal impairment (CrCl <30 mL/min): Reduce dose to enoxaparin 30 mg subcutaneously once daily 3
• Pregnancy: For pregnant women with acute superficial vein thrombosis, LMWH is suggested over no anticoagulation (conditional recommendation) 1
• Obesity (BMI >30 kg/m²): Consider intermediate doses of 40 mg subcutaneously every 12 hours or weight-based dosing at 0.5 mg/kg every 12 hours 3

Important Clinical Caveats

• Always perform ultrasound imaging to confirm the diagnosis and exclude concomitant deep vein thrombosis, which occurs in approximately 25% of patients with superficial thrombophlebitis 1
• Superficial thrombosis of the cephalic and basilic veins (upper extremity) does not require anticoagulant therapy 1
• The risk of pulmonary embolism with untreated superficial thrombophlebitis is approximately 1.3%, which justifies anticoagulation for lesions ≥5 cm 1
• Monitor platelet counts every 2-3 days from day 4 to day 14 to screen for heparin-induced thrombocytopenia 3

Duration and Monitoring

• Complete the full 45-day course even if symptoms resolve earlier, as this duration has been validated in clinical trials 1
• Routine anti-Xa monitoring is not necessary for prophylactic dosing in most patients 3
• For severe renal impairment on prolonged therapy, consider monitoring anti-Xa levels with target range of 0.5-1.5 IU/mL, measured 4-6 hours after the third or fourth dose 3