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fondaparinux

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Brand names: Arixtra

Factor Xa Inhibitor (Injectable) Rx

Fondaparinux is a drug that helps prevent and treat blood clots. It is given as an injection under the skin.

Drug Shortage Alert

fondaparinux is currently listed as to be discontinued by the FDA. Affected manufacturer: Jiangsu Hengrui Pharmaceuticals Co. (US Agent eVenus Pharmaceutical Laboratories, Inc.).

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Drug Pricing (NADAC)

Generic Price

$17.08/unit

Generic Available

Yes (4 manufacturers)

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

What it does

This medicine can prevent deep vein thrombosis (DVT) after hip fracture, hip replacement, knee replacement, or abdominal surgery.

Common side effects

Bleeding

Key warnings

This medicine can cause bleeding around your spine if you get an epidural or spinal tap while taking it.

How It Works

Fondaparinux is a Factor Xa inhibitor. It works by blocking a substance in your blood called Factor Xa. Blocking Factor Xa helps to prevent blood clots from forming.

How to Take It

Fondaparinux is given as a shot under your skin. Do not mix it with other medicines. For DVT prevention after surgery, the first dose is given 6 to 8 hours after surgery. The usual treatment lasts 5 to 9 days, but may be longer after hip fracture surgery.

Pregnancy & Breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant. Fondaparinux can cross the placenta and may increase the risk of bleeding in the fetus. Talk to your doctor about the risks and benefits of using this medicine during pregnancy.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.

Storage

Store at room temperature, between 68°F to 77°F.

Side Effects (from patient reports)

Based on 3,781 FDA adverse event reports.

Low red blood cell count
610
Collection of blood outside of a blood vessel (bruise)
559
Blood clot in the lungs
442
Using the medicine for a purpose not approved by the FDA
365
Bleeding
349
Decrease in the amount of hemoglobin in the blood
336
Death
298
Blood clot in a deep vein
293
Difficulty breathing
269
Low platelet count
260

FDA Adverse Event Report Analysis

Detailed analysis of 7,980 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.

Total Reports

7,980

Death-Related Reports

1,436

Hospitalization Reports

4,235

Top Indication

Product Used For Unknown Indication

Gender Distribution

Female 4,133 (56%)
Male 3,157 (43%)

Age Distribution

0–17 65
18–44 668
45–64 1,615
65–74 1,289
75+ 1,683

Most Reported Adverse Reactions (FAERS)

# Reaction Reports
1 ANAEMIA 610
2 HAEMATOMA 558
3 PULMONARY EMBOLISM 441
4 OFF LABEL USE 365
5 HAEMORRHAGE 348
6 HAEMOGLOBIN DECREASED 335
7 DEATH 296
8 DEEP VEIN THROMBOSIS 293
9 DYSPNOEA 269
10 THROMBOCYTOPENIA 260
11 DRUG INEFFECTIVE 258
12 PYREXIA 240
13 NAUSEA 234
14 THROMBOSIS 233
15 VOMITING 230

Reactions in Death Reports

DEATH 294
CEREBRAL HAEMORRHAGE 124
PULMONARY EMBOLISM 117
ANAEMIA 84
HAEMORRHAGE 78
SHOCK HAEMORRHAGIC 76
HAEMATOMA 69
SEPSIS 69
OFF LABEL USE 63
COMA 62

Reactions in Hospitalization Reports

ANAEMIA 476
HAEMATOMA 429
PULMONARY EMBOLISM 270
HAEMOGLOBIN DECREASED 221
OFF LABEL USE 221
DYSPNOEA 191
DEEP VEIN THROMBOSIS 190
ABDOMINAL PAIN 177
MUSCLE HAEMORRHAGE 172
THROMBOCYTOPENIA 169

Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation

Serious Warnings

This medicine can cause bleeding around your spine if you get an epidural or spinal tap while taking it. This bleeding can cause long-term or permanent paralysis. Tell your doctor if you are scheduled for a spinal procedure. Watch for signs of nerve damage like back pain, numbness, tingling, or weakness in your legs, or problems with bowel or bladder control. If you notice any of these symptoms, get medical help right away.

Known Drug Interactions

7 DRUG INTERACTIONS In clinical studies performed with fondaparinux sodium, the concomitant use of oral anticoagulants (warfarin), platelet inhibitors (acetylsalicylic acid), NSAIDs (piroxicam), and digoxin did not significantly affect the pharmacokinetics/pharmacodynamics of fondaparinux sodium. In addition, fondaparinux sodium neither influenced the pharmacodynamics of warfarin, acetylsalicylic acid, piroxicam, and digoxin, nor the pharmacokinetics of digoxin at steady state.

Mechanism: These drugs do not change how the body handles each other or how well they work to thin the blood.

What to do: No special dose adjustments are needed when using these medications at the same time.

minor digoxin

7 DRUG INTERACTIONS In clinical studies performed with fondaparinux sodium, the concomitant use of oral anticoagulants (warfarin), platelet inhibitors (acetylsalicylic acid), NSAIDs (piroxicam), and digoxin did not significantly affect the pharmacokinetics/pharmacodynamics of fondaparinux sodium. In addition, fondaparinux sodium neither influenced the pharmacodynamics of warfarin, acetylsalicylic acid, piroxicam, and digoxin, nor the pharmacokinetics of digoxin at steady state.

Mechanism: These medicines do not interfere with each other's levels or how they function in the body.

What to do: You can take these together without any special changes to your treatment plan.

7 DRUG INTERACTIONS In clinical studies performed with fondaparinux sodium, the concomitant use of oral anticoagulants (warfarin), platelet inhibitors (acetylsalicylic acid), NSAIDs (piroxicam), and digoxin did not significantly affect the pharmacokinetics/pharmacodynamics of fondaparinux sodium. In addition, fondaparinux sodium neither influenced the pharmacodynamics of warfarin, acetylsalicylic acid, piroxicam, and digoxin, nor the pharmacokinetics of digoxin at steady state.

Mechanism: These drugs do not have a significant impact on how the other is absorbed or used by the body.

What to do: No specific action is required when taking these two medications together.

Common Questions

What should I avoid while taking fondaparinux?
Talk to your doctor before taking other medicines that can increase your risk of bleeding, like NSAIDs (such as ibuprofen or naproxen), aspirin, or other blood thinners.
How will I know if I'm bleeding too much?
Watch for signs of bleeding, such as unusual bruising, nosebleeds, bleeding gums, blood in your urine or stool, or heavy menstrual bleeding. Tell your doctor right away if you notice any of these signs.
Can I take fondaparinux if I have kidney problems?
You should not take fondaparinux if you have severe kidney problems. Talk to your doctor about whether this medicine is right for you if you have kidney problems.
Will fondaparinux interact with my other medications?
Fondaparinux does not usually interact with many medications. However, it is important to tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
How long will I need to take fondaparinux?
The length of treatment depends on why you are taking fondaparinux. For DVT prevention after surgery, it is usually taken for 5 to 9 days. For hip fracture surgery, it may be taken for up to 32 days.
Can fondaparinux cause an allergic reaction?
In rare cases, fondaparinux can cause a serious allergic reaction. Get medical help right away if you have any signs of an allergic reaction, such as hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.
What should I do before any surgery or dental procedure?
Tell your doctor or dentist that you are taking fondaparinux before any surgery or dental procedure. You may need to stop taking it for a short time before the procedure to reduce your risk of bleeding.
Can I drink alcohol while taking fondaparinux?
Talk to your doctor about whether it is safe for you to drink alcohol while taking fondaparinux. Alcohol can increase your risk of bleeding.
What if I accidentally inject too much fondaparinux?
If you inject too much fondaparinux, get medical help right away. Overdosing on fondaparinux can increase your risk of serious bleeding.
Will fondaparinux make me feel tired?
Fondaparinux does not commonly cause tiredness. If you feel unusually tired, talk to your doctor.
What are the common side effects of fondaparinux?
The most commonly reported side effects of fondaparinux include Bleeding. Based on 3,781 FDA adverse event reports. Always consult your healthcare provider about potential side effects.
Does fondaparinux interact with other medications?
Yes, fondaparinux has 3 known drug interactions. Notable interactions include warfarin, digoxin, piroxicam. Always inform your doctor about all medications you are taking.
What drug class is fondaparinux?
fondaparinux belongs to the Factor Xa Inhibitor (Injectable) drug class. It requires a prescription (Rx). This medicine can prevent deep vein thrombosis (DVT) after hip fracture, hip replacement, knee replacement, or abdominal surgery.
Is fondaparinux safe during pregnancy?
Tell your doctor if you are pregnant or plan to become pregnant. Fondaparinux can cross the placenta and may increase the risk of bleeding in the fetus. Always consult your healthcare provider before using any medication during pregnancy or breastfeeding.
Is fondaparinux currently in shortage?
Yes, fondaparinux is currently listed as to be discontinued by the FDA. Affected manufacturer: Jiangsu Hengrui Pharmaceuticals Co. (US Agent eVenus Pharmaceutical Laboratories, Inc.). Visit the FDA Drug Shortages database for the latest updates.

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What the FDA Data Shows for fondaparinux

The FDA label for fondaparinux (sold under brand names such as Arixtra) classifies it as a prescription-only medication in the Factor Xa Inhibitor (Injectable) class. This medicine can prevent deep vein thrombosis (DVT) after hip fracture, hip replacement, knee replacement, or abdominal surgery. Official labeling lists 1 commonly reported side effect, including Bleeding.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 3,781 voluntary reports. The database also lists 3 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $17.08.

Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC). Shortage status: FDA Drug Shortages Database.

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.

Last updated: September 10, 2021

All federal data sources used on this page