FONDAPARINUX SODIUM
| FONDAPARINUX SODIUM (fon-da-par'i-nux) Arixtra Classifications: anticoagulant, selective factor xa inhibitor; Therapeutic: anticoagulant Pregnancy Category: B |
Availability
2.5 mg/0.5 mL, 5 mg/0.4 mL, 7.5 mg/0.6 mL, 10 mg/0.8 mL syringe
Action
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 Effect
Effective in the prevention and treatment of deep-vein thrombosis measured by the laboratory value of 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
| DVT, Pulmonary Embolism Prophylaxis Adult: SC >50 kg, 2.5 mg q.d. starting at least 6 h postsurgery times 5–9 d; for hip fracture patients, up to 24 d additional use Treatment of DVT, Pulmonary Embolism Adult: SC <50 kg, 5 mg; 50–100 kg, 7.5 mg; >100 kg, 10 mg once daily x 5–9 d Renal Impairment Clcr 30–50 mL/min: use with caution; <30 mL/min: use is contraindicated |
Administration
Subcutaneous- 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%)
Body as a Whole: Fever, edema. CNS: Insomnia, dizziness, confusion, headache. CV: Hypotension. GI: Nausea, constipation, vomiting, diarrhea, dyspepsia, elevated LFTs. Endocrine: Hypokalemia. Hematologic: Hemorrhage, anemia, hematoma. Skin: Irritation at injection site, rash, purpura, bullous eruption. Urogenital: UTI, urinary retention.Interactions
Drug: anticoagulants, antiplatelets, nsaids, aspirin may increase risk of bleeding. Herbal: Feverfew, ginkgo, ginger may potentiate bleeding.Pharmacokinetics
Absorption: Rapidly and completely absorbed from SC injection site. Peak: 2–3 h. Distribution: Primarily in blood. Metabolism: Negligible metabolism. Elimination: In urine. Half-Life: 18 h.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. Lab test for measuring drug effectiveness is amount of anti-Xa assay expressed in mg. (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.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug