fondaparinux (Rx)

Brand and Other Names:Arixtra
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Dosing & Uses


Dosage Forms & Strengths

prefilled syringe

  • 2.5mg/0.5mL
  • 5mg/0.4mL
  • 7.5mg/0.6mL
  • 10mg/0.8mL

Deep Vein Thrombosis/Acute Pulmonary Embolism


  • <50 kg: 5 mg SC once daily
  • 50-100 kg: 7.5 mg SC once daily
  • >100 kg: 10 mg SC once daily
  • Administer for 5-9 days; up to 26 days administered in clinical trials


  • >50 kg: 2.5 mg SC once daily for 5-9 days or up to 10 days following abdomonal surgery; for hip replacement, 11 days recommended and a minimum 10-14 days recommended for patients undergoing total hip or knee arthroplasty, or hip fracture surgery; administered for up to 35 days in some instances

VTE Prophylaxis With History of HIT (Off-label)

Prophylaxis of deep vein thrombosis (DVT) in patient with history of heparin-induced thrombocytopenia (HIT) until patient can switch to warfarin

2.5 mg SC once daily for 5-10 days

American College of Chest Physicians (ACCP) guidelines assign low evidence rating to treatment of HIT with fondaparinux and conclude that further studies evaluating its role in HIT treatment are needed


Administer initial dose 6-8 hours after surgery, once hemostasis has been established

SC administration is deep, alternating right and left anterior and posterior abdominal walls

Safety and efficacy not established

Because bleeding is increased in adults <50 kg, bleeding may be a particular safety concern in children



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            Adverse Effects


            Anemia (1-20%)

            Fever (4-14%)

            Nausea (3-11%)


            Rash (7.5%)

            Dizziness (4%)

            Confusion (3%)

            Constipation (5-9%)

            Diarrhea (2-3%)

            Edema (9%)

            Headache (2-5%)

            Hypokalemia (1-4%)

            Hypotension (4%)

            Insomnia (4-5%)

            Purpura (4%)

            Thrombocytopenia (3%)

            Urinary retention (3%)

            Urinary tract infection (2-4%)

            Vomiting (1-6%)

            Postmarketing Reports

            Thrombocytopenia with thrombosis that manifested similarly to HIT

            Serious allergic reactions, including angioedema and anaphylactoid or anaphylactic reactions

            Spinal or epidural hematomas


            Increase in bleeding risk with renal impairment

            Increase in bleeding risk with body weight <50 Kg

            Increase in aminotransferase levels



            Black Box Warnings

            Epidural or spinal hematomas may occur in patients undergoing anticoagulation with low-molecular-weight heparins (LMWHs) or heparinoids who receive neuraxial (epidural or spinal) anesthesia or spinal puncture

            These hematomas may result in long-term or permanent paralysis

            Patients should be frequently monitored for signs and symptoms of neurologic impairment

            If neurologic compromise is noted, urgent treatment is necessary

            Physicians should weigh benefits against risk before embarking on neuraxial intervention in patients anticoagulated or scheduled to be anticoagulated for thromboprophylaxis

            Optimal timing between the administration of LMWHs and neuraxial procedures is not known

            Factors increasing risk of epidural or spinal hematomas

            • Indwelling epidural catheters
            • Concomitant use of other drugs that affect hemostasis (eg, nonsteroidal anti-inflammatory drugs [NSAIDs], platelet inhibitors, other anticoagulants)
            • History of traumatic or repeated epidural or spinal punctures
            • History of spinal deformity or spinal surgery


            Severe renal impairment (CrCl <30 mL/min)

            Body weight <50 kg (venous thromboembolism prophylaxis only)

            Active major bleeding

            Bacterial endocarditis

            Thrombocytopenia with antiplatelet antibody in presence of fondaparinux

            History of serious hypersensitivity reaction (eg, angioedema, anaphylactoid or anaphylactic reactions)


            Use with caution in the elderly (prolonged half-life in patients >75 years of age), peptic ulcer disease, bleeding disorder, recent stroke, recent surgery (brain, spinal cord, or eye), concurrent use of platelet inhibitors or anticoagulants, moderate renal impairment (CrCl 30-50 mL/min); may cause prolonged anticoagulation in patients with CrCl 30 to 50 mL/min

            Discontinue if platelets <100,000/μL

            Not for IM administration

            Therapy increases risk of hemorrhage in patients at risk for bleeding, including conditions such as congenital or acquired bleeding disorders, active ulcerative and angiodysplastic gastrointestinal disease, hemorrhagic stroke, uncontrolled arterial hypertension, diabetic retinopathy, or shortly after brain, spinal, or ophthalmological surgery; cases of elevated aPTT temporally associated with bleeding events have been reported following administration of drug (with or without concomitant administration of other anticoagulants); do not administer agents that enhance risk of hemorrhage unless essential for management of underlying condition, such as vitamin K antagonists for treatment of VTE; if co-administration is essential, closely monitor patients for signs and symptoms of bleeding

            Do not use interchangeably with heparin or LMWHs

            Thrombocytopenia with thrombosis reported with use; discontinue therapy if platelet count falls below 100,000/mm³

            Risk of spinal or epidural hematomas if spinal puncture occurs (see Black Box Warnings)

            Do not administer initial dose earlier than 6- 8 hours after surgery; administration earlier than 6 hours after surgery increases risk of major bleeding

            Increased risk of bleeding in patients <50 kg; dosage reduction recommended

            Not for administration as prophylactic for patients undergoing hip fracture, hip replacement, or knee replacement surgery and abdominal surgery


            Pregnancy & Lactation


            Available data from published literature and postmarketing reports have not reported clear association with adverse developmental outcomes; fondaparinux sodium plasma concentrations obtained from four women treated during pregnancy and their newborn infants demonstrated low placental transfer of fondaparinux sodium; there are risks to mother associated with untreated venous thromboembolism in pregnancy and a risk of hemorrhage in the mother and fetus associated with use of anticoagulants

            Pregnancy confers an increased risk for thromboembolism that is higher for women with underlying thromboembolic disease and certain high-risk pregnancy conditions; published data describe that women with a previous history of venous thrombosis are at high risk for recurrence during pregnancy

            Fetal/neonatal adverse reactions

            • Drug has been demonstrated to cross placenta in humans; use of anticoagulants, may increase risk of bleeding in the fetus and neonate; monitor neonates for bleeding

            Labor or delivery

            • All patients receiving anticoagulants, including pregnant women, are at risk for bleeding; use during labor or delivery in women who are receiving neuraxial anesthesia may result in epidural or spinal hematomas; pregnant women receiving therapy should be carefully monitored for evidence of bleeding or unexpected changes in coagulation parameters; consideration for use of a shorter acting anticoagulant should be specifically addressed as delivery approaches


            There are no data on presence in human milk, or effects on milk production; limited clinical data during lactation preclude a clear determination of risk of therapy to an infant during lactation; therefore, developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from therapy or from underlying maternal condition

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action

            Antithrombotic agent; inhibits factor Xa, which interrupts blood coagulation cascade and inhibits thrombin formation and thrombus development; generally does not increase prothrombin time (PT) or partial thromboplastin time (PTT)


            Bioavailability: 100%

            Peak plasma time: 2-3 hr

            Peak plasma concentration: 0.34-0.50 mg/L


            Protein bound: 94% (antithrombin III)

            Vd: 7-11 L


            Not established


            Half-life: 17-21 hr

            Dialyzable: Yes

            Excretion: Urine





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            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
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