Fondaparinux Injections

ExitCare ImageFondaparinux (Arixtra®) injection is a blood thinner (anticoagulant) medication that "thins" the blood and helps to prevent blood clots from developing in your veins. If blood clots develop and are left untreated, they can travel to your heart, lungs, or brain. These clots can cause serious illness and can be fatal. Blood clots can form due to:

  • Prolonged immobility such as:

  • People who cannot get out of bed (bedridden).

  • Sitting for long periods of time, such as long airplane flights.

  • Surgery, especially operations that involve:

  • Orthopedic (bones and joints).

  • The abdomen.

  • Obesity.

  • Certain heart conditions.

  • Certain cancers.

  • Hormone Replacement Therapy (HRT) or birth control pills (uncommon but possible).


If a blood clot has developed, caregivers can use fondaparinux to treat clots in the legs or lungs. In addition to fondaparinux, another blood thinner called warfarin (Coumadin®) will be started 2 to 3 days after fondaparinux has been started. warfarin is a pill and must be taken simultaneously with fondaparinux until the warfarin has begun to work.

Your caregiver may use a blood test called an INR or International Normalization Ratio to know when there is enough warfarin in the blood. Fondaparinux may be stopped when the INR level is between 2.0 to 3.0. This means that your blood is at the necessary and best level to treat the clots that have formed.


In Europe, fondaparinux is sometimes used to help when there is not enough blood flow to the heart.


  • Fondaparinux should not be used if you have allergies to the medication, heparin or pork products.

  • Before giving your medication, make sure the solution is a clear and colorless. If your medication becomes discolored or has particles in the bottle, do not use it. Notify your caregiver right away.

  • Keep your medication safely stored at room temperatures.

  • You will be instructed by your caregiver how to give fondaparinux injections.


  1. Fondaparinux is a shot that is given in the stomach (abdomen). Change (rotate) the injection site each time you give yourself a shot.

  2. Twist the plunger cap and remove it.

  3. 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. Discard the needle guard.

  4. When using the pre-filled syringes, do not expel the air bubble from the syringe before the injection. The air bubble helps to inject all of the medication when it is given.

  5. The injection will be given just underneath the skin into the fat of the belly (subcutaneously). The shots should be injected around the outside of the belly (abdominal wall). Change the place where you give the shot each time. The whole length of the needle should be introduced into a skin fold held between the thumb and forefinger; the skin fold should be held throughout the injection.

  6. Inject fondaparinux by pushing the plunger to the bottom of the syringe. Push the plunger rod firmly with your thumb as far as it will go. This will ensure you have injected all of the medication. Do no t rub the injection site after completion of the injection. This increases bruising.

  7. Remove the syringe from the injection site, keeping your finger on the plunger rod. Be careful not to stick yourself or others.

  8. Fondaparinux injection pre-filled syringes and graduated pre-filled syringes are available with a system that shields the needle after injection. After injection and the syringe is empty, set off the safety system by firmly pushing the plunger rod. The protective sleeve will automatically cover the needle and you can hear a click. The click means your needle is safely covered.

  9. Get rid of the syringe in the nearest needle box (sharps container).


Problems with fondaparinux are rare. However, side effects and complications can occur, such as:

  • Serious side effects can include:

  • If you are taking fondaparinux or other low-molecular-weight heparins and have an epidural or spinal anesthesia or a spinal tap, you are at risk of developing a blood clot in or around the spine. This condition could result in long-term or permanent paralysis.

  • A condition called heparin-induced thrombocytopenia (HIT) can occur with fondaparinux use. This is where your platelet count drops. HIT is rare. However, your caregiver will perform lab work to check your blood levels. If you have had this condition before, you should tell your caregiver.

  • Because fondaparinux thins your blood, complications may include bleeding into the bowel or kidneys.

  • Mild side effects may include:

  • Bruising around the injection site.

  • Mild irritation at the site of injection, such as pain, itching, or redness of skin.


  • You develop bleeding problems such as:

  • Vomiting blood or coughing up blood.

  • Blood in your urine.

  • Blood in your stool or your stool has a dark, tarry, or coffee ground appearance.

  • You develop any rashes on your skin, such as:

  • Multiple red "dots."

  • Long red streaks.

  • You have large areas of bruising on your skin.

  • A sudden nosebleed that does not stop after 15 to 20 minutes.

  • You have any worsening of the condition that led you to fondaparinux treatment.

  • You develop chest pain or shortness of breath. If the chest pain or shortness of breath is severe, call your local emergency service immediately!


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.