Availability

2.5 mg/0.5 mL, 5 mg/0.4 mL, 7.5 mg/0.6 mL, 10 mg/0.8 mL syringe

Actions

Fondaparinux sodium causes antithrombin III (ATIII)-mediated selective inhibition of Factor Xa. Fondaparinux selectively binds to ATIII, potentiating the innate neutralization of Factor Xa by ATIII. Neutralization of Factor Xa by fondaparinux interrupts the blood coagulation cascade, inhibiting thrombin formation and, thus, thrombus development. Fondaparinux sodium does not inactivate thrombin (activated Factor II) and has no known effect on platelet function, therefore, it rarely causes thrombocytopenia.

Therapeutic Effects

Fondaparinux is effective in the prevention and treatment of deep-vein thrombosis. The laboratory value utilized to determine the effectiveness of the drug is the amount of anti-Xa assay expressed in mg.

Uses

Prophylaxis for DVT or pulmonary embolism (PE) in patients undergoing hip or knee replacement surgery or abdominal surgery; treatment of acute DVT without PE with warfarin, treatment of PE with warfarin.

Contraindications

Hypersensitivity to fondaparinux; active bleeding; GI bleeding; severe renal impairment with a creatinine clearance of <30 mL/min; weight <50 kg; active major bleeding; bacterial endocarditis; intramuscular administration; thrombocytopenia associated with fondaparinux. Safety and effectiveness in children have not been established.

Cautious Use

Renal impairment or disease; older adult; indwelling epidural catheter; dental disease, dental work; diabetic retinopathy; diverticulitis; endocarditis, epidural anesthesia; hemophilia, heparin-induced thrombocytopenia (HIT), hepatic disease, hypertension, idiopathic thrombocytopenia purpura (ITP); inflammatory bowel disease, lumbar puncture, spinal anesthesia; stroke, surgery; thrombocytopenia, thrombolytic therapy; vaginal bleeding, menstruation; peptic ulcer disease; pregnancy (category B); bleeding disorders including a history of GI ulceration, etc., history of heparininduced thrombocytopenia; lactation.

Route & Dosage

Administration

• Consult physician about discontinuing other agents that may enhance the risk of hemorrhage prior to initiation of fondaparinux.
• Give no sooner than 6 h after surgery.
• Adjust doses in older adults based on renal function.
• Inspect visually for particulate matter and discoloration prior to administration.
• Do not expel the air bubble from the syringe before the injection.
• Use prefilled syringe to inject into fatty tissue, alternating injection sites (e.g., between L and R abdominal wall).
• Store at 25° C (77° F); excursions permitted to 15°–30° C (59°–86° F).

Adverse Effects (1%)

Interactions

Pharmacokinetics

Nursing Implications

Assessment & Drug Effects

• Monitor for S&S of bleeding or hemorrhage. If noted, withhold fondaparinux and notify physician immediately.
• Monitor closely patients with epidural catheters for signs of paralysis below catheter level.
• Withhold fondaparinux and notify physician if platelet count falls below 100,000/mm³.
• Lab tests: Monitor baseline and periodic renal function rests; periodic CBC including platelet count, serum creatinine level, and stool occult blood tests. (Note: PT and aPTT are relatively insensitive measures of fondaparinux activity and unsuitable for monitoring.)

Patient & Family Education

• Report any of the following to a health care provider: signs of unexplained bleeding such as: pink, red, or dark brown urine; red or dark brown vomitus; bleeding gums or bloody sputum; dark, tarry stools.
• Learn proper injection technique if you are to self-administer this drug.
• Do not take any OTC drugs without first consulting physician.
• Do not breast feed while taking this drug without consulting physician.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug