fondaparinux

General

High Alert Medication: This medication bears a heightened risk of causing significant patient harm when it is used in error.

Pronunciation
fon-da-PAR-i-nux

Trade Name(s)

• Arixtra

Indications

Prevention and treatment of deep vein thrombosis and pulmonary embolism.

Unlabelled Use(s):
Systemic anticoagulation for other diagnoses.

Action

Binds selectively to antithrombin III (AT III). This binding potentiates the neutralization (inactivation) of active factor X (Xa).

Therapeutic Effect(s):
Interruption of the coagulation cascade resulting in inhibition of thrombus formation. Prevention of thrombus formation decreases the risk of pulmonary emboli.

Pharmacokinetics

Absorption: 100% absorbed following subcutaneous administration.

Distribution: Distributes mainly throughout the intravascular space.

Metabolism and Excretion: Eliminated mainly unchanged in urine.

Half-life: 17–21 hr.

TIME/ACTION PROFILE (anticoagulant effect)

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity;

• Severe renal impairment (CCr <30 mL/min; ↑ risk of bleeding);

• Body weight <50 kg (for prophylaxis) (markedly ↑ risk of bleeding);

• Active major bleeding;

• Bacterial endocarditis;

• Thrombocytopenia due to fondaparinux antibodies.

• Mild-to-moderate renal impairment (CCr 30–50 mL/min);

• Untreated hypertension;

• Recent history of ulcer disease;

• Body weight <50 kg (for treatment of DVT or PE) (may ↑ risk of bleeding);

• Geri: Patients >65 yr (↑ risk of bleeding);

• Malignancy;

• History of heparin-induced thrombocytopenia;

• OB: Lactation: Pedi: Safety not established; use during pregnancy only if clearly needed.

• History of congenital or acquired bleeding disorder;

• Severe uncontrolled hypertension;

• Hemorrhagic stroke;

• Recent CNS or ophthalmologic surgery;

• Active GI bleeding/ulceration;

• Retinopathy (hypertensive or diabetic);

• Spinal/epidural anesthesia or spinal puncture (↑ risk of spinal/epidural hematoma that may lead to long-term or permanent paralysis).

Adverse Reactions/Side Effects

CNS: confusion, dizziness, headache, insomnia.

CV: edema, hypotension.

GI: constipation, diarrhea, dyspepsia, ↑ liver enzymes, nausea, vomiting.

GU: urinary retention.

Derm: bullous eruption, hematoma, purpura, rash.

Hemat: bleeding, thrombocytopenia.

F and E: hypokalemia.

Misc: fever, ↑ wound drainage.

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug
Risk of bleeding may be ↑ by concurrent use of warfarin or drugs that affect platelet function , including aspirin , NSAIDs , dipyridamole , some cephalosporins , valproates , clopidogrel , ticlopidine , abciximab , eptifibatide , tirofiban , and dextran .

Drug-Natural Products
↑ risk of bleeding with arnica , chamomile , clove , dong quai , feverfew , garlic , ginger , gingko , Panax ginseng , and others.

Route/Dosage

Treatment of DVT/PE

• SC (Adults): <50 kg—5 mg once daily for at least 5 days until therapeutic anticoagulation with warfarin is achieved (INR >2 for 2 consecutive days); warfarin may be started within 72 hr of fondaparinux (has been used for up to 26 days); 50–100 kg—7.5 mg once daily for at least 5 days until therapeutic anticoagulation with warfarin is achieved (INR >2 for 2 consecutive days); >100 kg—10 mg once daily for at least 5 days until therapeutic anticoagulation with warfarin is achieved (INR >2 for 2 consecutive days); warfarin may be started within 72 hr of fondaparinux..

• SC (Adults): 2.5 mg once daily, starting 6–8 hr after surgery, continuing for 5–9 days (up to 11 days) following abdominal surgery or knee/hip replacement or continuing for 24 days following hip fracture surgery (up to 32 days)..

Availability

• Solution for subcut injection: 2.5 mg/0.5 mL in prefilled syringes, 5 mg/0.4 mL in prefilled syringes, 7.5 mg/0.6 mL in prefilled syringes, 10 mg/0.8 mL in prefilled syringes

Assessment

• Assess for signs of bleeding and hemorrhage (bleeding gums; nosebleed; unusual bruising; black, tarry stools; hematuria; fall in hematocrit; sudden drop in BP; guaiac positive stools); bleeding from surgical site. Notify health care professional if these occur.

• Assess for evidence of additional or increased thrombosis. Symptoms will depend on area of involvement. Monitor neurological status frequently for signs of impairment, especially in patients with indwelling epidural catheters for administration of analgesia or with concomitant use of drugs affecting hemostasis (NSAIDs, platelet inhibitors, other anticoagulants). Risk is increased by traumatic or repeated epidural or spinal puncture. May require urgent treatment.

• Monitor platelet count closely; may cause thrombocytopenia. If platelet count is <100,000/mm³, discontinue fondaparinux.

» Fondaparinux is not accurately measured by prothrombin time (PT), activated thromboplastin time (aPTT), or international standards of heparin or low molecular weight heparins. If unexpected changes in coagulation parameters or major bleeding occurs, discontinue fondaparinux.

» Monitor CBC, serum creatinine levels, and stool occult blood tests routinely during therapy.

» May cause asymptomatic ↑ in AST and ALT. Elevations are fully reversible and not associated with ↑ in bilirubin.

» May cause ↑ aPTT temporally associated with bleeding with or without concomitant administration of other anticoagulants and thrombocytopenia with thrombosis similar to heparin-induced thrombocytopenia, with or without exposure to heparin or low-molecular-weight heparin.

Potential Nursing Diagnoses

• Ineffective tissue perfusion (Indications)

• Risk for injury (Side Effects)

Implementation

• Fondaparinux cannot be used interchangeably with heparin, low-molecular-weight heparins, or heparinoids as they differ in manufacturing process, anti-Xa and anti-IIa activity, units, and dose. Each of these medications has its own instructions for use.

» Initial dose should be administered 6-8 hr after surgery. Administration before 6 hr after surgery has been associated with risk of major bleeding.

• SC: Administer subcut only into fatty tissue, alternating sites between right and left anterolateral or posterolateral abdominal wall. Inject entire length of needle at a 45° or 90° angle into a skin fold held between thumb and forefinger; hold skin fold throughout injection. Do not aspirate or massage. Rotate sites frequently. Do not administer IM because of danger of hematoma formation. Solution should be clear; do not inject solution containing particulate matter. Do not mix with other injections.

» Fondaparinux is provided in a single-dose prefilled syringe with an automatic needle protection system. Do not expel air bubble from prefilled syringe before injection to prevent loss of drug.

Patient/Family Teaching

• Advise patient to report any symptoms of unusual bleeding or bruising, dizziness, itching, rash, fever, swelling, or difficulty breathing to health care professional immediately.

• Instruct patient not to take aspirin or NSAIDs without consulting health care professional during therapy.

Evaluation/Desired Outcomes

Prevention and treatment of deep vein thrombosis and pulmonary embolism.