Achievement of Therapeutic Anti-Xa Levels in a Proven Heparin-Resistant Patient Through the Use of Nontraditional High-Dose Enoxaparin

Abstract

Objective: To describe the successful use of high-dose enoxaparin therapy (1.5 mg/kg subcutaneously twice daily) to attain a therapeutic anti–factor Xa (anti-Xa) level in a cancer patient with heparin resistance. Case Summary: A proven heparin-resistant patient with venous thromboembolism (VTE) and lung cancer who required approximately 66 000 units of unfractionated heparin daily was successfully transitioned to an off-label high-dose enoxaparin (OLHDE) 1.5 mg/kg subcutaneously twice daily. The patient was maintained on this same dose, and therapeutic levels were confirmed via use of the anti-Xa monitoring test. The patient was able to be discharged from the medical floor on this same dose with no further complications of VTE noted. No adverse events from this dosing were observed during the duration of therapy. Discussion: Options for overcoming heparin resistance are limited to case reports and small studies. The best course of treatment in the cancer patient is unclear. OLHDE allowed for the transition from intravenous to subcutaneous medication and transition off the medical floor. This case supports the use of OLHDE as a therapeutic option in heparin-resistant patients with cancer. Further study is needed to confirm the efficacy of OLHDE in this patient population. Conclusion: High-dose enoxaparin may be an option to treat cancer patients with confirmed heparin resistance and venous thromboembolism.