Prescription medication · Factor Xa Inhibitor (Injectable)
fondaparinux
Also sold as Arixtra. This medicine can prevent deep vein thrombosis (DVT) after hip fracture, hip replacement, knee replacement, or abdominal surgery.
Data updated 2026-05-15
- 7,980
- FDA reportsLightly reported
- 3
- InteractionsFew interactions
- In shortage
- FDA status
What the data shows
fondaparinux (Arixtra) is a prescription Factor Xa Inhibitor (Injectable), reported less often than most tracked drugs (7,980 FDA reports), with 3 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
fondaparinux (Arixtra) is a prescription Factor Xa Inhibitor (Injectable). This medicine can prevent deep vein thrombosis (DVT) after hip fracture, hip replacement, knee replacement, or abdominal surgery.
Fondaparinux is a drug that helps prevent and treat blood clots. It is given as an injection under the skin.
Verify with FDA → · CMS NADAC pricing →
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.).
View all drug shortages →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.
The sections below are summarized in plain English from fondaparinux's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
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.
This is a plain-language summary of fondaparinux's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
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.
This is a plain-language summary of fondaparinux's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
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.
This is a plain-language summary of fondaparinux's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store at room temperature, between 68°F to 77°F.
Side Effects (from patient reports)
Based on 7,980 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for fondaparinux, by number of reports
- Low red blood cell count
Low red blood cell count
610 reports
- Collection of blood outside of a blood vessel (bruise)
Collection of blood outside of a blood vessel (bruise)
559 reports
- Blood clot in the lungs
Blood clot in the lungs
442 reports
- Bleeding
Bleeding
349 reports
- Decrease in the amount of hemoglobin in the blood
Decrease in the amount of hemoglobin in the blood
336 reports
- Death
Death
298 reports
- Blood clot in a deep vein
Blood clot in a deep vein
293 reports
- Difficulty breathing
Difficulty breathing
269 reports
- Low platelet count
Low platelet count
260 reports
- Fever 240
Fever
240 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for fondaparinux each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where fondaparinux sits
fondaparinux has more FDA adverse-event reports than 35% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is fondaparinux; the line is the median (50th percentile).
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
Reports Mentioning Death
1,436
18.0% of reports — not proof of cause
Hospitalization Reports
4,235
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | ANAEMIA | 610 |
| 2 | HAEMATOMA | 558 |
| 3 | PULMONARY EMBOLISM | 441 |
| 5 | HAEMORRHAGE | 348 |
| 6 | HAEMOGLOBIN DECREASED | 335 |
| 7 | DEATH | 296 |
| 8 | DEEP VEIN THROMBOSIS | 293 |
| 9 | DYSPNOEA | 269 |
| 10 | THROMBOCYTOPENIA | 260 |
| 12 | PYREXIA | 240 |
| 13 | NAUSEA | 234 |
| 14 | THROMBOSIS | 233 |
| 15 | VOMITING | 230 |
| 16 | DRUG INTERACTION | 228 |
| 17 | MUSCLE HAEMORRHAGE | 215 |
Reactions in Death Reports
Reactions in Hospitalization Reports
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.
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.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
What should I avoid while taking fondaparinux?
How will I know if I'm bleeding too much?
Can I take fondaparinux if I have kidney problems?
Will fondaparinux interact with my other medications?
How long will I need to take fondaparinux?
Can fondaparinux cause an allergic reaction?
What should I do before any surgery or dental procedure?
Can I drink alcohol while taking fondaparinux?
What if I accidentally inject too much fondaparinux?
Will fondaparinux make me feel tired?
What are the common side effects of fondaparinux?
Does fondaparinux interact with other medications?
What drug class is fondaparinux?
Is fondaparinux safe during pregnancy?
Is fondaparinux currently in shortage?
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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 7,980 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
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages