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Fondaparinux

Pronunciation

Pronunciation

(fon da PARE i nuks)

Index Terms

  • Fondaparinux Sodium

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Subcutaneous, as sodium:

Generic: 2.5 mg/0.5 mL (0.5 mL); 5 mg/0.4 mL (0.4 mL); 7.5 mg/0.6 mL (0.6 mL); 10 mg/0.8 mL (0.8 mL)

Solution, Subcutaneous, as sodium [preservative free]:

Arixtra: 2.5 mg/0.5 mL (0.5 mL); 5 mg/0.4 mL (0.4 mL); 7.5 mg/0.6 mL (0.6 mL); 10 mg/0.8 mL (0.8 mL)

Generic: 2.5 mg/0.5 mL (0.5 mL); 5 mg/0.4 mL (0.4 mL); 7.5 mg/0.6 mL (0.6 mL); 10 mg/0.8 mL (0.8 mL)

Brand Names: U.S.

  • Arixtra

Pharmacologic Category

  • Anticoagulant
  • Anticoagulant, Factor Xa Inhibitor

Pharmacology

Fondaparinux is a synthetic pentasaccharide that causes an antithrombin III-mediated selective inhibition of factor Xa. Neutralization of factor Xa interrupts the blood coagulation cascade and inhibits thrombin formation and thrombus development.

Absorption

SubQ: Rapid and complete

Distribution

Vd: 7 to 11 L; mainly in blood

Excretion

Urine (up to 77%, unchanged drug)

Time to Peak

SubQ: ~2 to 3 hours

Half-Life Elimination

17 to 21 hours; prolonged with renal impairment and in the elderly

Protein Binding

≥94% to antithrombin III

Special Populations: Renal Function Impairment

Elimination is prolonged.

Special Populations: Hepatic Function Impairment

In patients with moderate hepatic impairment (Child-Pugh class B), Cmax and AUC were decreased by 22% and 39%, respectively.

Special Populations: Elderly

Elimination is prolonged in patients older than 75 years.

Special Populations Note

Body weight: Total clearance is decreased approximately 30% in patients weighing less than 50 kg.

Use: Labeled Indications

Acute deep vein thrombosis: Treatment of acute deep vein thrombosis (DVT) in conjunction with warfarin.

Acute pulmonary embolism: Treatment of acute pulmonary embolism (PE) in conjunction with warfarin.

Deep vein thrombosis prophylaxis: Prophylaxis of DVT in patients undergoing surgery for hip replacement, knee replacement, hip fracture (including extended prophylaxis following hip fracture surgery), or abdominal surgery (in patients at risk for thromboembolic complications).

Canadian labeling: Additional uses; not approved in the US: Management of unstable angina or non-ST segment elevation myocardial infarction (UA/NSTEMI) for the prevention of death and subsequent MI; management of ST segment elevation MI (STEMI) for the prevention of death and myocardial reinfarction

Use: Unlabeled

Prophylaxis of DVT in patients with a history of heparin-induced thrombocytopenia (HIT); treatment of acute thrombosis (unrelated to HIT) in patients with a past history of HIT; acute symptomatic superficial vein thrombosis (≥5 cm in length) of the legs

Contraindications

Serious hypersensitivity (eg, angioedema, anaphylactoid/anaphylactic reactions) to fondaparinux or any component of the formulation; severe renal impairment (CrCl <30 mL/minute); body weight <50 kg (prophylaxis); active major bleeding; bacterial endocarditis; thrombocytopenia associated with a positive in vitro test for antiplatelet antibody in the presence of fondaparinux

Dosing: Adult

Note: PT and aPTT are insensitive measures of fondaparinux activity. If unexpected changes in coagulation parameters or major bleeding occur, discontinue fondaparinux.

DVT prophylaxis: SubQ: Adults ≥50 kg: 2.5 mg once daily. Note: Prophylactic use contraindicated in patients <50 kg. Initiate dose after hemostasis has been established, no earlier than 6 to 8 hours postoperatively.

DVT prophylaxis with history of HIT (off-label use): SubQ: 2.5 mg once daily (Blackmer 2009; Harenberg 2004; Parody 2003)

Usual duration: 5 to 9 days (up to 10 days following abdominal surgery or up to 11 days following hip fracture, hip replacement, or knee replacement was administered in clinical trials). The American College of Chest Physicians recommends a minimum of 10 to 14 days for patients undergoing total hip arthroplasty, total knee arthroplasty, or hip fracture surgery; extended duration of up to 35 days suggested (Guyatt 2012).

Acute DVT/PE treatment: SubQ: Note: Start warfarin on the first or second treatment day and continue fondaparinux until INR is ≥2 for at least 24 hours (usually 5 to 7 days) (Guyatt 2012):

<50 kg: 5 mg once daily

50 to 100 kg: 7.5 mg once daily

>100 kg: 10 mg once daily

Usual duration: 5 to 9 days (administered up to 26 days in clinical trials)

Acute coronary syndrome (Canadian labeling; off-label use in US):

UA/NSTEMI: SubQ: 2.5 mg once daily; treat for the duration of hospitalization or until PCI performed (ACC/AHA [Amsterdam 2014])

STEMI: IV: 2.5 mg once; subsequent doses (starting the following day): SubQ: 2.5 mg once daily; treat for the duration of the hospitalization, up to 8 days, or until revascularization (ACCF/AHA [O’Gara 2013]; Yusuf 2006b)

Acute symptomatic superficial vein thrombosis (≥5 cm in length) of the legs (off-label use): SubQ: 2.5 mg once daily for 45 days (Decousus 2010; Guyatt 2012)

Acute thrombosis (unrelated to HIT) in patients with a past history of HIT (off-label use) (Guyatt 2012; Warkentin 2011): SubQ:

<50 kg: 5 mg once daily

50 to 100 kg: 7.5 mg once daily

>100 kg: 10 mg once daily

Dosing: Geriatric

Refer to adult dosing.

Dosing: Renal Impairment

CrCl >50 mL/minute: There are no dosage adjustments provided in the manufacturer’s labeling. Total clearance is reduced ~25% compared to patients with normal renal function.

CrCl 30 to 50 mL/minute: Use caution; total clearance ~40% lower compared to patients with normal renal function. When used for thromboprophylaxis, the American College of Chest Physicians suggests a 50% reduction in dose or use of low-dose heparin instead of fondaparinux (Garcia 2012).

CrCl <30 mL/minute: Use is contraindicated.

Dosing: Hepatic Impairment

Mild-to-moderate impairment (Child-Pugh class A and B): No dosage adjustment necessary; monitor for signs of bleeding.

Severe impairment (Child-Pugh class C): There are no dosage adjustment provided in the manufacturer's labeling (has not been studied). Use with caution; monitor closely for signs of bleeding.

Reconstitution

Canadian labeling: For IV administration: May mix with 25 mL or 50 mL NS

Administration

For SubQ administration; do not administer IM. Alternate injection sites. Do not expel air bubble from syringe before injection. Administer according to recommended regimen; when used for DVT prophylaxis, early initiation (before 6 hours after orthopedic surgery) has been associated with increased bleeding. For STEMI patients (Canadian labeling; off-label use in United States) may administer initial dose as IV push or mix in NS and infuse over 1 to 2 minutes; flush tubing with NS after infusion to ensure complete administration for fondaparinux.

To convert from IV unfractionated heparin (UFH) infusion to SubQ fondaparinux (Nutescu 2007): Calculate specific dose for fondaparinux based on indication, discontinue UFH, and begin fondaparinux within 1 hour

To convert from SubQ fondaparinux to IV UFH infusion (Nutescu 2007): Discontinue fondaparinux; calculate specific dose for IV UFH infusion based on indication; omit heparin bolus/loading dose

For subQ fondaparinux dosed every 24 hours: Start IV UFH infusion 22 to 23 hours after last dose of fondaparinux

Compatibility

Do not mix with other injections or infusions.

Canadian labeling: Stable in NS

Storage

Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

Canadian labeling: Store <25°C (77°F); do not freeze. For IV infusion, use immediately once diluted in NS; can also be stored for up to 24 hours at 15°C to 30°C (59°F to 86°F).

Drug Interactions

Agents with Antiplatelet Properties (e.g., P2Y12 inhibitors, NSAIDs, SSRIs, etc.): May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Apixaban: May enhance the anticoagulant effect of Anticoagulants. Refer to separate drug interaction content and to full drug monograph content regarding use of apixaban with vitamin K antagonists (eg, warfarin, acenocoumarol) during anticoagulant transition and bridging periods. Avoid combination

Collagenase (Systemic): Anticoagulants may enhance the adverse/toxic effect of Collagenase (Systemic). Specifically, the risk of injection site bruising and/or bleeding may be increased. Monitor therapy

Dabigatran Etexilate: May enhance the anticoagulant effect of Anticoagulants. Refer to separate drug interaction content and to full drug monograph content regarding use of dabigatran etexilate with vitamin K antagonists (eg, warfarin, acenocoumarol) during anticoagulant transition and bridging periods. Avoid combination

Dasatinib: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Deferasirox: Anticoagulants may enhance the adverse/toxic effect of Deferasirox. Specifically, the risk for GI ulceration/irritation or GI bleeding may be increased. Monitor therapy

Deoxycholic Acid: Anticoagulants may enhance the adverse/toxic effect of Deoxycholic Acid. Specifically, the risk for bleeding or bruising in the treatment area may be increased. Monitor therapy

Desirudin: Anticoagulants may enhance the anticoagulant effect of Desirudin. Consider therapy modification

Edoxaban: May enhance the anticoagulant effect of Anticoagulants. Refer to separate drug interaction content and to full drug monograph content regarding use of edoxaban with vitamin K antagonists (eg, warfarin, acenocoumarol) during anticoagulant transition and bridging periods. Management: Some limited combined use may be indicated during periods of transition from one anticoagulant to another. See the full edoxaban drug monograph for specific recommendations on switching anticoagulant treatment. Avoid combination

Estrogen Derivatives: May diminish the anticoagulant effect of Anticoagulants. More specifically, the potential prothrombotic effects of some estrogens and progestin-estrogen combinations may counteract anticoagulant effects. Management: Carefully weigh the prospective benefits of estrogens against the potential increased risk of procoagulant effects and thromboembolism. Use is considered contraindicated under some circumstances. Refer to related guidelines for specific recommendations. Exceptions: Tibolone. Consider therapy modification

Factor X (Human): Anticoagulants (Inhibitors of Factor Xa) may diminish the therapeutic effect of Factor X (Human). Monitor therapy

Hemin: May enhance the anticoagulant effect of Anticoagulants. Avoid combination

Herbs (Anticoagulant/Antiplatelet Properties) (eg, Alfalfa, Anise, Bilberry): May enhance the adverse/toxic effect of Anticoagulants. Bleeding may occur. Consider therapy modification

Ibritumomab: Anticoagulants may enhance the adverse/toxic effect of Ibritumomab. Both agents may contribute to an increased risk of bleeding. Monitor therapy

Ibrutinib: May enhance the adverse/toxic effect of Anticoagulants. Monitor therapy

Limaprost: May enhance the adverse/toxic effect of Anticoagulants. The risk for bleeding may be increased. Monitor therapy

Nintedanib: Anticoagulants may enhance the adverse/toxic effect of Nintedanib. Specifically, the risk for bleeding may be increased. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Obinutuzumab: Anticoagulants may enhance the adverse/toxic effect of Obinutuzumab. Specifically, the risk of serious bleeding-related events may be increased. Monitor therapy

Omacetaxine: Anticoagulants may enhance the adverse/toxic effect of Omacetaxine. Specifically, the risk for bleeding-related events may be increased. Management: Avoid concurrent use of anticoagulants with omacetaxine in patients with a platelet count of less than 50,000/uL. Avoid combination

Omega-3 Fatty Acids: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Pentosan Polysulfate Sodium: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Progestins: May diminish the therapeutic effect of Anticoagulants. More specifically, the potential prothrombotic effects of some progestins and progestin-estrogen combinations may counteract anticoagulant effects. Management: Carefully weigh the prospective benefits of progestins against the potential increased risk of procoagulant effects and thromboembolism. Use is considered contraindicated under some circumstances. Refer to related guidelines for specific recommendations. Consider therapy modification

Prostacyclin Analogues: May enhance the adverse/toxic effect of Anticoagulants. Specifically, the antiplatelet effects of these agents may lead to an increased risk of bleeding with the combination. Monitor therapy

Rivaroxaban: Anticoagulants may enhance the anticoagulant effect of Rivaroxaban. Refer to separate drug interaction content and to full drug monograph content regarding use of rivaroxaban with vitamin K antagonists (eg, warfarin, acenocoumarol) during anticoagulant transition and bridging periods. Avoid combination

Salicylates: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Sugammadex: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Thrombolytic Agents: May enhance the anticoagulant effect of Anticoagulants. Management: See full drug monograph for guidelines for the use of alteplase for acute ischemic stroke during treatment with oral anticoagulants. Monitor therapy

Tibolone: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Tipranavir: May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Tositumomab and Iodine I 131 Tositumomab: Anticoagulants may enhance the adverse/toxic effect of Tositumomab and Iodine I 131 Tositumomab. Specifically, the risk of bleeding-related adverse effects may be increased. Monitor therapy

Urokinase: May enhance the anticoagulant effect of Anticoagulants. Avoid combination

Vitamin E (Systemic): May enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Anticoagulants may enhance the anticoagulant effect of Vitamin K Antagonists. Monitor therapy

Vorapaxar: May enhance the adverse/toxic effect of Anticoagulants. More specifically, this combination is expected to increase the risk of bleeding. Avoid combination

Test Interactions

International standards of heparin or LMWH are not the appropriate calibrators for antifactor Xa activity of fondaparinux.

Adverse Reactions

As with all anticoagulants, bleeding is the major adverse effect. Hemorrhage may occur at any site. Risk appears increased by a number of factors including renal dysfunction, age (>75 years), and weight (<50 kg).

>10%: Hematologic & oncologic: Anemia (2% to 20%)

1% to 10%:

Cardiovascular: Hypotension (≤4%)

Central nervous system: Insomnia (≤5%), dizziness (≤4%), confusion (1% to 3%)

Dermatologic: Increased wound secretion (≤5%), skin blister (≤3%)

Endocrine & metabolic: Hypokalemia (≤4%)

Hematologic & oncologic: Purpura (≤4%), thrombocytopenia (50,000 to 100,000/mm3: 3%), hematoma (2% to 3%), minor hemorrhage (2% to 3%), major hemorrhage (1% to 3%; risk of major hemorrhage increased as high as 5% in patients receiving initial dose <6 hours following surgery), postoperative hemorrhage (≤2%)

Hepatic: Increased serum ALT (>3 × ULN: 1% to 3%), increased serum AST (>3 × ULN: <1% to ≤2%)

Infection: Postoperative wound infection (abdominal surgery: 5%)

Respiratory: Epistaxis (VTE: 1%)

<1% (Limited to important or life-threatening): Anaphylactoid reaction, anaphylaxis, angioedema, catheter site thrombosis (during PCI; without heparin), elevated aPTT associated with bleeding, epidural hematoma, hemorrhagic death, injection site reaction (bleeding at injection site, skin rash, pruritus), intracranial hemorrhage, reoperation due to bleeding, severe thrombocytopenia (<50,000/mm3), spinal hematoma, thrombocytopenia (with thrombosis)

ALERT: U.S. Boxed Warning

Spinal/Epidural hematomas:

Epidural or spinal hematomas may occur in patients who are anticoagulated with low molecular weight heparins, heparinoids, or fondaparinux and are receiving neuraxial anesthesia or undergoing spinal puncture. These hematomas may result in long-term or permanent paralysis. Consider these risks when scheduling patients for spinal procedures. Factors that can increase the risk of developing epidural or spinal hematomas in these patients include use of indwelling epidural catheters; concomitant use of other drugs that affect hemostasis, such as nonsteroidal anti-inflammatory drugs (NSAIDs), platelet inhibitors, or other anticoagulants; a history of traumatic or repeated epidural or spinal puncture; or a history of spinal deformity or spinal surgery. Optimal timing between the administration of fondaparinux and neuraxial procedures is not known.

Monitor patients frequently for signs and symptoms of neurologic impairment. If neurologic compromise is noted, urgent treatment is necessary.

Consider the benefit and risks before neuraxial intervention in patients anticoagulated or to be anticoagulated for thromboprophylaxis.

Warnings/Precautions

Concerns related to adverse effects:

• Bleeding: Monitor patient closely for signs or symptoms of bleeding. Certain patients are at increased risk of bleeding. Risk factors include bacterial endocarditis; congenital or acquired bleeding disorders; active ulcerative and angiodysplastic GI disease; uncontrolled arterial hypertension; hemorrhagic stroke; recent intracranial hemorrhage; or use shortly after brain, spinal, or ophthalmology surgery; in patients treated concomitantly with platelet inhibitors; or thrombocytopenia or platelet defects; diabetic retinopathy; patients <50 kg. Risk of major bleeding may be increased if initial dose is administered earlier than recommended (initiation recommended at 6 to 8 hours following surgery). Do not administer with other agents that increase the risk of hemorrhage unless they are essential for the management of the underlying condition (eg, vitamin K antagonists for treatment of VTE). PT and aPTT are insensitive measures of fondaparinux activity. If unexpected changes in coagulation parameters or major bleeding occur, discontinue fondaparinux (elevated aPTT associated with bleeding events have been reported in postmarketing data).

• Thrombocytopenia: Has occurred with administration, including very rare reports of thrombocytopenia with thrombosis similar to heparin-induced thrombocytopenia (HIT); however, has been used in patients with current or history of HIT due to a lack of an immune-mediated effect on platelets (ACCP [Guyatt 2012]; Savi 2005). Use is contraindicated in patients with thrombocytopenia associated with a positive in vitro test for antiplatelet antibodies in the presence of fondaparinux. Monitor patients closely and discontinue therapy if platelets fall to <100,000/mm3 (US labeling) or < 50,000/ mm3 (Canadian labeling).

Disease-related concerns:

• Hepatic impairment: May increase the risk of bleeding in patients with hepatic impairment. Use with caution.

• Renal impairment: May increase the risk of bleeding in patients with renal impairment. Use with caution in patients with CrCl 30 to 50 mL/minute; contraindicated in patients with CrCl <30 mL/minute. Periodically monitor renal function; discontinue if severe renal dysfunction or labile function develops.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Elderly: Use with caution in the elderly; increased risk of bleeding in patients >75 years of age.

• Patients <50 kg: Increased risk of bleeding in patients <50 kg; use with caution; dosage reduction recommended. Contraindicated in patients <50 kg when used for prophylactic therapy.

Dosage form specific issues:

• Latex: The needle guard may contain natural latex rubber.

Other warnings/precautions:

• Appropriate use: For subcutaneous administration; not for IM administration. For STEMI patients (Canadian labeling; off-label use in United States) may administer initial dose IV. Do not use interchangeably (unit for unit) with low molecular weight heparins, heparin, or heparinoids.

• Discontinuation: Following discontinuation, the anticoagulant effects of fondaparinux may persist for 2 to 4 days and even longer in patients with renal impairment.

• Neuraxial anesthesia: [U.S. Boxed Warning]: Spinal or epidural hematomas, including subsequent long-term or permanent paralysis, may occur with recent or anticipated neuraxial anesthesia (epidural or spinal anesthesia) or spinal puncture in patients anticoagulated with LMWH, heparinoids, or fondaparinux. Consider risk versus benefit prior to spinal procedures; risk is increased by the use of concomitant agents which may alter hemostasis (such as NSAIDS, platelet inhibitors, or other anticoagulants), the use of indwelling epidural catheters, a history of spinal deformity or spinal surgery, as well as a history of traumatic or repeated epidural or spinal punctures. Patient should be observed closely for bleeding and signs and symptoms of neurological impairment (eg, midline back pain, sensory and motor deficits [numbness, tingling, weakness in lower limbs], bowel or bladder dysfunction) if therapy is administered during or immediately following diagnostic lumbar puncture, epidural anesthesia, or spinal anesthesia. Optimal timing between administration of fondaparinux and neuraxial procedures is unknown.

• Percutaneous coronary intervention (PCI): The administration of fondaparinux as the sole anticoagulant is not recommended during PCI due to an increased risk for guiding-catheter thrombosis. Use of an anticoagulant with antithrombin activity (eg, unfractionated heparin) is recommended as adjunctive therapy to PCI even if prior treatment with fondaparinux (must take into account whether GP IIb/IIIa antagonists have been administered) (ACC/AHA [Amsterdam 2014]; Levine 2011). Use of fondaparinux during primary PCI is not recommended. In STEMI patients undergoing primary PCI for reperfusion, the use of fondaparinux prior to and during PCI is not recommended (Canadian labeling).

Monitoring Parameters

Periodically monitor CBC, platelet count, serum creatinine, and occult blood testing of stools. Anti-Xa activity of fondaparinux can be measured by the assay if fondaparinux is used as the calibrator.

Pregnancy Risk Factor

B

Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies. Based on case reports, small amounts of fondaparinux have been detected in the umbilical cord following multiple doses during pregnancy (Dempfle 2004). Use of fondaparinux in pregnancy should be limited to those women who have severe allergic reactions to heparin, including heparin-induced thrombocytopenia, and who cannot receive danaparoid (Guyatt 2012).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience injection site irritation or insomnia. Have patient report immediately to prescriber signs of bleeding (vomiting blood or vomit that looks like coffee grounds, coughing up blood, blood in the urine, black, red, or tarry stools, bleeding from the gums, abnormal vaginal bleeding, bruises without a reason or that get bigger, or any bleeding that is very bad or that you cannot stop), severe dizziness, syncope, a fall hitting head, illogical thinking, severe headache, paresthesia, or loss of strength or energy (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing, chest tightness, fever, itching, bad cough, blue skin color, seizures, or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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