Subcutaneous Unfractionated Heparin for Treatment of Venous Thromboembolism in End-Stage Renal Disease

OBJECTIVE: To report 3 cases of venous thromboembolism (VTE) in patients with end-stage renal disease (ESRD) treated with subcutaneous unfractionated heparin (UFH) bridged with warfarin. CASE SUMMARIES: Three patients with ESRD were successfully treated for VTE with unmonitored, fixed-dose subcutaneous UFH every 12 hours and dose-adjusted warfarin. The first patient was initiated on continuous infusion UFH for deep-vein thrombosis, but due to poor vascular access, nurses were unable to consistently measure anti-Xa levels. Therefore, subcutaneous UFH 17,500 units (similar to 245 units/kg/dose) every 12 hours was initiated. Oral warfarin 5 mg/day was started the following day. The patient received 4 days of inpatient subcutaneous UFH and then was discharged to complete the bridge as an outpatient. The second patient received subcutaneous UFH 10,000 units (similar to 244 units/kg/dose) every 12 hours and oral warfarin 2.5 mg/day to treat a nonocclusive thrombus along her right femoral vein hemodialysis catheter. The patient received 1 day of inpatient subcutaneous UFH treatment prior to discharge and continued bridge therapy with warfarin as an outpatient. The third patient was initiated on subcutaneous UFH 20,000 units (similar to 223 units/kg/dose) every 12 hours and oral warfarin 7.5 mg/day due to a subtherapeutic INR (1.50) 5 days after receiving fresh frozen plasma to reduce her therapeutic INR for a procedure. The patient received 2 doses of subcutaneous UFH as an inpatient before treatment was discontinued because her INR was therapeutic at 2.3. DISCUSSION: Subcutaneous UFH has been used to treat VTE since the early 1980s; however, with the advent of low-molecular-weight heparin (LMWH), subcutaneous UFH use diminished. Several studies comparing the use of subcutaneous UFH to both continuous infusion UFH and LMWH concluded that subcutaneous UFH is a safe and efficacious alternative. The 2008 Chest Guidelines for Antithrombotic Therapy for Venous Thromboembolic Disease support the use of subcutaneous UFH for the treatment of VTE with a Grade 1A recommendation and provide a Grade 2C recommendation for use of UFH over LMWH for patients with VTE and severe renal failure. CONCLUSIONS: Safe and convenient treatment options for VTE in patients with ESRD are limited. Fixed-dose, unmonitored subcutaneous UFH as a bridge to warfarin therapy is an effective option in patients with ESRD and those with financial restrictions. The pharmacist plays a key role in identifying patients for whom subcutaneous UFH treatment may be a viable alternative, recommending an appropriate dosing regimen, and educating health-care professionals and patients about safe use.