Skip to main content

Arixtra Dosage

Generic name: FONDAPARINUX SODIUM 2.5mg in 0.5mL
Dosage form: injection, solution
Drug class: Factor Xa inhibitors

Medically reviewed by Drugs.com. Last updated on Dec 10, 2024.

Important Dosing Information

Do not mix other medications or solutions with ARIXTRA. Administer ARIXTRA only subcutaneously. Discard unused portion.

Monitor routine complete blood counts (including platelet count), serum creatinine level, and stool occult blood periodically.

Deep Vein Thrombosis Prophylaxis Following Hip Fracture, Hip Replacement, and Knee Replacement Surgery in Adults

In adult patients undergoing hip fracture, hip replacement, or knee replacement surgery, the recommended dose of ARIXTRA is 2.5 mg administered by subcutaneous injection once daily after hemostasis has been established. Administer the initial dose no earlier than 6 hours to 8 hours after surgery. Administration of ARIXTRA earlier than 6 hours after surgery increases the risk of major bleeding. The usual duration of therapy is 5 days to 9 days; up to 11 days of therapy was administered in clinical trials.

In patients undergoing hip fracture surgery, an extended prophylaxis course of up to 24 additional days is recommended. In patients undergoing hip fracture surgery, a total of 32 days (peri-operative and extended prophylaxis) was administered in clinical trials.

Deep Vein Thrombosis Prophylaxis Following Abdominal Surgery in Adults

In adult patients undergoing abdominal surgery, the recommended dose of ARIXTRA is 2.5 mg administered by subcutaneous injection once daily after hemostasis has been established. Administer the initial dose no earlier than 6 hours to 8 hours after surgery. Administration of ARIXTRA earlier than 6 hours after surgery increases the risk of major bleeding. The usual duration of administration is 5 days to 9 days, and up to 10 days of ARIXTRA was administered in clinical trials.

Deep Vein Thrombosis and Pulmonary Embolism Treatment in Adults

In adult patients with acute symptomatic DVT and in patients with acute symptomatic PE, the recommended dose of ARIXTRA is 5 mg (body weight less than 50 kg), 7.5 mg (body weight 50 kg to 100 kg), or 10 mg (body weight greater than 100 kg) by subcutaneous injection once daily (ARIXTRA treatment regimen). Initiate concomitant treatment with warfarin sodium as soon as possible, usually within 72 hours. Continue treatment with ARIXTRA for at least 5 days and until a therapeutic oral anticoagulant effect is established (INR 2 to 3). The usual duration of administration of ARIXTRA is 5 days to 9 days; up to 26 days of ARIXTRA injection was administered in clinical trials.

Venous Thromboembolism Treatment in Pediatric Patients Aged 1 Year or Older Weighing at Least 10 kg

For patients weighing 10 kg to 20 kg, the recommended initial dose is 0.1 mg/kg subcutaneously once daily. There is no available prefilled syringe for patients in this weight range, and a patient specific dose should be prepared (see section 2.8 Instructions for Preparation of Individual Pediatric Doses in Pharmacies). The dose should be exact and rounded to the nearest 0.1 mg (see Table 1).

Table 1. Recommended Initial Dose of ARIXTRA for Treatment of VTE in Pediatric Patients Weighing 10 kg to 20 kg

Body Weight (kg)

Initial Dose

10 kg to 20 kg

Dosing should be exact and rounded to the nearest 0.1 mg

For patients weighing over 20 kg, the recommended initial dose is 0.1 mg/kg subcutaneously once daily with doses rounded to the nearest prefilled syringe according to Table 2.

There is no available information for dosing pediatric patients who weigh less than 10 kg.

Table 2. Recommended Prefilled Syringe Selection for Initial Dose of ARIXTRA for Treatment of VTE in Pediatric Patients Weighing More Than 20 kg
*
Whenever possible, patients weighing more than 20 kg should receive a full prefilled syringe for dosing. If therapeutic levels are not achievable using the prefilled syringe available strengths and dose adjustments are needed, a patient specific dose may be prepared (see section 2.8 Instructions for Preparation of Individual Pediatric Doses in Pharmacies).

Body Weight (kg)

Prefilled Syringe Selection

Greater than 20 kg to 40 kg*

2.5 mg/0.5 mL

Greater than 40 kg to 60 kg*

5 mg/0.4 mL

Greater than 60 kg*

7.5 mg/0.6 mL

Monitor fondaparinux levels 2 hours to 4 hours after the second or third dose and then weekly for a month followed by every 1 month to 3 months for the duration of treatment using a fondaparinux-based anti-Xa assay with a therapeutic goal range of 0.5 mg/L to 1 mg/L.

Dosing adjustments may be necessary to achieve peak blood concentration within the therapeutic target of 0.5 mg/L to 1 mg/L (see Table 3). Do not exceed the maximum dose of 7.5 mg/day.

Table 3. Recommended Dose Adjustments
*
Adjust the dose to the nearest 0.1 mg.

Fondaparinux-Based Anti-Xa Level (mg/L)

Dose Adjustment

Less than 0.3 mg/L

Increase dose by 0.03 mg/kg*

0.3 mg/L to 0.49 mg/L

Increase dose by 0.01 mg/kg*

0.5 mg/L to 1 mg/L

No change

1.01 mg/L to 1.2 mg/L

Decrease dose by 0.01 mg/kg*

Greater than 1.2 mg/L

Decrease dose by 0.03 mg/kg*

There is no adequate data to support the use of ARIXTRA in pediatric patients below 1 year of age.

Hepatic Impairment

No dose adjustment is recommended in patients with mild to moderate hepatic impairment, based upon single-dose pharmacokinetic data. Pharmacokinetic data are not available for patients with severe hepatic impairment. Patients with hepatic impairment may be particularly vulnerable to bleeding during ARIXTRA therapy. Observe these patients closely for signs and symptoms of bleeding.

Instructions for Use for Prefilled Syringe

ARIXTRA Injection is provided in a single-dose, prefilled syringe affixed with an automatic needle protection system. ARIXTRA is administered by subcutaneous injection. It must not be administered by intramuscular injection. ARIXTRA is intended for use under a physician’s guidance. Patients may self-inject only if their physician determines that it is appropriate, and the patients are trained in subcutaneous injection techniques.

Prior to administration, visually inspect ARIXTRA to ensure the solution is clear and free of particulate matter.

To avoid the loss of drug when using the prefilled syringe, do not expel the air bubble from the syringe before the injection. Administration should be made in the fatty tissue, alternating injection sites (e.g., between the left and right anterolateral or the left and right posterolateral abdominal wall).

To administer ARIXTRA:

1.
Wipe the surface of the injection site with an alcohol swab.
2.
Hold the syringe with either hand and use your other hand to twist the rigid needle guard (covers the needle) counter-clockwise. Pull the rigid needle guard straight off the needle (Figure A). Discard the needle guard.
2.7 Figure A
3.
Do not try to remove the air bubbles from the syringe before giving the injection.
4.
Pinch a fold of skin at the injection site between your thumb and forefinger and hold it throughout the injection.
5.
Hold the syringe with your thumb on the top pad of the plunger rod and your next 2 fingers on the finger grips on the syringe barrel. Pay attention to avoid sticking yourself with the exposed needle.
6.
Insert the full length of the syringe needle perpendicularly into the skin fold held between the thumb and forefinger (Figure B).
2.7 Figure B
7.
Push the plunger rod firmly with your thumb as far as it will go. This will ensure you have injected all the contents of the syringe (Figure C).
2.7 Figure C
8.
When you have injected all the contents of the syringe, the plunger should be released. The plunger will then rise automatically while the needle withdraws from the skin and retracts into the security sleeve. Discard the syringe into the sharps container.
9.
You will know that the syringe has worked when:
The needle is pulled back into the security sleeve and the white safety indicator appears above the upper body.
You may also hear or feel a soft click when the plunger rod is released fully.

Instructions for Preparation of Individual Pediatric Doses in Pharmacies

For pediatric patients weighing 10 kg to 20 kg, a patient-specific dose may be prepared by a pharmacist under aseptic conditions per the instructions below.

These instructions may also be used to prepare pediatric patient-specific doses for patients weighing over 20 kg when dose adjustments are needed and therapeutic levels are not achievable using the prefilled syringe available strengths.

Prior to preparing ARIXTRA, visually inspect ARIXTRA prefilled syringe to ensure the solution is clear and free of particulate matter.

General Aseptic Preparation Practices

Strictly observe aseptic technique when preparing patient specific pediatric doses of ARIXTRA. To prevent accidental contamination, prepare ARIXTRA according to aseptic standards, including but not limited to:

Prepare ARIXTRA in an ISO Class 5 laminar airflow (LAF) hood
Ensure that the dose preparation area, including the LAF hood, has appropriate environmental specifications, confirmed by periodic monitoring.
Ensure that personnel are appropriately trained in aseptic manipulations of sterile products.
Ensure that personnel wear appropriate clothing and gloves.
Ensure that gloves and surfaces are disinfected.

All steps should be completed in accordance with aseptic techniques:

1.
Determine the total dose and volume per the duration, and the appropriate number of ARIXTRA prefilled syringes. One ARIXTRA prefilled syringe is used in cases where the total required dose is less than 0.5 mL. Where the total dose required is greater than or equal to 0.5 mL, only two ARIXTRA prefilled syringes may be pooled together. The maximum number of ARIXTRA prefilled syringes that may be pooled together is two.

Do not combine ARIXTRA prefilled syringes of different concentrations in one injection to give the prescribed dose.
2.
Gather the required supplies including the appropriate ARIXTRA prefilled syringe(s), a sterile, closed/sealed, empty glass vial (recommended 5 mL), and required number of suitable sized graduated tuberculin sterile syringes with 27 gauge x ½” staked needles or sterile needles (if not pre-attached to syringe).
3.
Verify the required supplies are correct and within expiry date. Ensure only the materials required for the preparation are present in the work area.
4.
While wearing sterile gloves, clean the LAF hood and wipe it down with sterile 70% alcohol. Ensure the LAF hood is within specification and continually monitored.
5.
Ensure equipment and consumables are cleaned with isopropyl alcohol (IPA).
6.
Before transferring into the LAF hood, clean all supplies including ancillary items (such as vial holder jigs, syringe cap holder jigs, sharps containers) with IPA.
7.
Perform all the dose preparation steps within the LAF hood.
8.
Pre-sterilize gloves with IPA. While wearing sterile gloves, hold the ARIXTRA prefilled syringe with either gloved hand and use your other gloved hand to twist the rigid needle guard (covers the needle) counter-clockwise. Pull the rigid needle guard straight off the needle. Discard the needle guard.
9.
Dispense the full contents of the ARIXTRA prefilled syringe into the vial by fully depressing the plunger.
10.
When you have injected all the contents of the ARIXTRA prefilled syringe, the plunger should be released. The plunger will then rise automatically while the needle retracts into the security sleeve. Discard the ARIXTRA prefilled syringe into a sharps container.
11.
Take an empty graduated tuberculin sterile syringe and attach a suitable sterile needle if not already supplied pre-attached.
12.
Remove needle cap.
13.
Withdraw required dose from vial into the tuberculin syringe.
14.
Replace needle cap over the needle. Clean the external surfaces of the filled tuberculin syringe with IPA.
15.
Repeat steps 11 to 14 as required for the appropriate number of tuberculin syringes necessary for the patient.
16.
Label each ARIXTRA tuberculin syringe with patient specific information (e.g., dosing instructions, patient information), storage information (e.g., store refrigerated between 36°F to 46°F (2°C to 8°C), do not freeze, and the beyond use date). The beyond use date should be the earlier of the product expiration date of the ARIXTRA prefilled syringe or 30 days after preparation of the tuberculin syringe.
17.
Prepared tuberculin syringes may be dispensed in an empty plastic bag. Include Patient Information and Instructions for Use for the tuberculin syringe within the plastic bag to be dispensed to patients. They may be stored at refrigerated temperatures between 36°F to 46°F (2°C to 8°C) for up to the beyond use date. Do not freeze.

Do not store the pediatric preparations at room temperature as they are growth promoting at room temperature.

Discard unused portion.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.