Are fondaparinux (Arixtra) injections preferable to warfarin (Coumadin) for management of anticoagulation in postoperative hip-fracture patients and those recovering from joint replacement surgery? Warfarin works just fine and prevents deep venous thrombosis (DVT) and pulmonary embolism for prolonged periods of time.
—Patricia White, ARNP, Vero Beach, Fla.
I was unable to find a head-to-head trial in the literature comparing Coumadin with Arixtra. However, each has clear benefits and drawbacks noted in the literature. Coumadin is easier to administer orally while Arixtra is given by subcutaneous (SC) injection. Coumadin has the additional benefit of extra-renal clearance and appears to be safe for patients with renal insufficiency. Because Arixtra is excreted unchanged by the kidneys, excretion is prolonged in patients with renal impairment. In fact, Arixtra is contraindicated in patients with severe renal impairment and creatinine clearance <30 mL/min. Another benefit Coumadin has over Arixtra is a safe and well-known antidote—vitamin K. For DVT prophylaxis, Arixtra is recommended at a standard 2.5-mg SC injection daily, which means that unlike Coumadin, there is no need to adjust dosing based on international normalized ratio (INR). For DVT treatment, Arixtra is prescribed as a weight-dependent dose and is overlapped with Coumadin until the INR is 2.0-3.0. Both Arixtra and Coumadin are effective in prevention of DVT in the post-op hip-fracture patient.
—Michael E. Zychowicz, DNP, NP-C (110-2)