Fondaparinux (patient information)
Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Fondaparinux ((fon-da-PA-rin-ux)) is used to prevent deep vein thrombosis, a condition in which harmful blood clots form in the blood vessels of the legs. These blood clots can travel to the lungs and can become lodged in the blood vessels of the lungs, causing a condition called pulmonary embolism. This medicine is used for several days after hip fracture surgery, hip replacement surgery or knee replacement surgery. It is also used in patients who are having abdominal surgery who are at risk for blood clots. Blood clots are more likely to form after surgery when you are unable to walk. Fondaparinux is also used to treat deep vein thrombosis and a condition called pulmonary embolism together with warfarin (e.g., Coumadin). Pulmonary embolism occurs when harmful blood clot form in the blood vessels in the lungs and is a very serious and sometimes fatal condition. Fondaparinux also may be used for other conditions as determined by your doctor.
This medicine is available only with your doctor's prescription, in the following dosage form:
Parenteral Injection (U.S.)
Before Using This Medicine
In deciding to use a medicine, the risks of using the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For fondaparinux, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to fondaparinux. Also tell your doctor and pharmacist if you are allergic to any other substances, such as foods, preservatives, or dyes.
Fondaparinux has not been studied in pregnant women. However, fondaparinux has not been shown to cause birth defects or other problems in animal studies. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.
It is not known whether fondaparinux passes into human breast milk. Because many medicines pass into breast milk, mothers who are taking this medicine and who wish to breast-feed should discuss this with their doctor.
Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of fondaparinux in children with use in other age groups.
Bleeding problems may be especially likely to occur in elderly patients, who are usually more sensitive than younger adults to the effects of fondaparinux.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Other medical problems
The presence of other medical problems may affect the use of fondaparinux. Make sure you tell your doctor if you have any other medical problems, especially:
- Blood disease or bleeding problems or
- Eye problems caused by diabetes or high blood pressure or
- Heart infection or
- High blood pressure (hypertension) or
- If you weigh less than 110 pounds or
- Kidney disease or
- Stomach or intestinal ulcer (active) or
- Stroke. The risk of bleeding may be increased.
Also, tell your doctor if you have received fondaparinux or heparin before and had a reaction to either of them called thrombocytopenia (a low platelet count in the blood), or if new blood clots formed while you were receiving the medicine.
In addition, tell your doctor if you have recently had medical surgery or spinal anesthesia. This may increase the risk of serious bleeding when you are taking fondaparinux.
Proper Use of This Medicine
If you are using fondaparinux at home, your health care professional will teach you how to inject yourself with the medicine. Be sure to follow the directions carefully. Check with your health care professional if you have any problems using the medicine .
Put used syringes in a puncture-resistant, disposable container , or dispose of them as directed by your health care professional.
The dose of fondaparinux will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of fondaparinux. If your dose is different, do not change it unless your doctor tells you to do so.
For injection dosage form:
- For prevention of deep vein thrombosis (leg clots)
- Adults: 2.5 milligrams (mg) injected under the skin once a day for five to nine days. The first dose is given six to eight hours after surgery.
- Children: Use and dose must be determined by your doctor.
- For treatment of deep vein thrombosis (leg clots) and pulmonary embolism (blood clots in the lungs)
- Adults: 5 milligrams (mg) (if body weight is less than 110 lbs), 7.5 mg (for 110 lbs to 220 lbs), or 10 mg (for greater than 220 lbs) injected under the skin once a day for five to nine days. The first dose is given six to eight hours after surgery. The doctor will determine when treatment with warfarin should begin.
- Children: Use and dose must be determined by your doctor.
Missed dose: If you miss a dose of this medicine, call your doctor.
To store this medicine:
- Keep out of the reach of children.
- Store away from heat and direct light.
- Keep the medicine from freezing. Do not refrigerate.
- Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.
Precautions While Using This Medicine
Tell all your medical doctors and dentists that you are using this medicine .
Check with your doctor immediately if you notice any of the following side effects:
Bruising or bleeding, especially bleeding that is hard to stop. (Bleeding inside the body sometimes appears as bloody or black, tarry stools. Feeling faint or vomiting blood are other signs of bleeding.)
Side Effects of This Medicine
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Pale skin; troubled breathing with exertion; unusual bleeding or bruising; unusual tiredness or weakness
Black, tarry stools; bladder pain; bleeding; bleeding gums; blood in urine or stools; blurred vision; chest pain; chills; collection of blood under skin; confusion; convulsions; cough; decreased or cloudy urine; deep, dark purple bruise; difficult, burning, or painful urination; dizziness; dry mouth; fainting or lightheadedness when getting up from a lying or sitting position; fever; frequent urge to urinate; increased thirst; irregular heartbeat; itching, pain, redness, or swelling at place of injection; loss of appetite; lower back or side pain; mood changes; muscle pain or cramps; nausea or vomiting; numbness or tingling in hands, feet, or lips; painful or difficult urination; pinpoint red spots on skin; red, tender, or oozing skin at incision; shortness of breath; sore throat; sores, ulcers, or white spots on lips or in mouth; sudden sweating
Symptoms of overdose
Get emergency help immediately if any of the following symptoms of overdose occur
- Abdominal pain or swelling; back pain; black, tarry, stools; bruising or purple areas on skin; coughing up blood
- Decreased alertness; dizziness; headache; joint pain or swelling; nosebleeds
Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome.
Difficulty having a bowel movement; fever; rash; sleeplessness; swelling; trouble sleeping
Acid or sour stomach; belching; diarrhea; headache; heartburn; indigestion; pain; pinpoint red or purple spots on skin; skin blisters; stomach discomfort, upset or pain; tightness in chest; unusual changes to site of surgery; wheezing; increased wound drainage.
Adapted from the FDA Package Insert.