Prescription medication · Unfractionated Heparin
heparin
Also sold as Heparin Sodium. Heparin is used to prevent and treat blood clots in your veins and lungs.
Data updated 2026-05-15
- 12,966
- FDA reportsModerately reported
- 20
- InteractionsSeveral interactions
- In shortage
- FDA status
What the data shows
heparin (Heparin Sodium) is a prescription Unfractionated Heparin, reported less often than most tracked drugs (12,966 FDA reports), with 20 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.
heparin (Heparin Sodium) is a prescription Unfractionated Heparin. Heparin is used to prevent and treat blood clots in your veins and lungs.
Heparin is a medicine that helps prevent and treat blood clots. It is given as an injection into a vein or under the skin.
Verify with FDA → · CMS NADAC pricing →
Drug Shortage Alert
heparin is currently listed as in shortage by the FDA. Affected manufacturer: Fresenius Kabi USA, LLC. Status: Available.
View all drug shortages →Drug Pricing (NADAC)
Generic Price
$2.17/unit
Generic Available
Yes (21 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Heparin is used to prevent and treat blood clots in your veins and lungs.
Common side effects
Bleeding, Irritation at the injection site, Allergic reactions
Key warnings
Heparin can cause serious bleeding, which can be fatal.
The sections below are summarized in plain English from heparin's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Heparin works by stopping certain proteins in your blood from forming clots. It helps to thin your blood and prevent new clots from forming. It does not dissolve existing blood clots, but it can keep them from getting bigger.
How to Take It
Heparin is given as an injection by a healthcare provider. It can be injected into a vein (intravenously) or under the skin (subcutaneously). The dose you receive will depend on your condition and weight. Your doctor will monitor your blood to make sure you are getting the right amount.
This is a plain-language summary of heparin's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
If you are pregnant, talk to your doctor about the risks and benefits of using heparin. Preservative-free heparin is recommended during pregnancy if available. It is not known if heparin passes into breast milk, so it is recommended to avoid breastfeeding while using this medicine.
This is a plain-language summary of heparin's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
Since heparin is given by a healthcare provider, you are unlikely to miss a dose. If you are giving yourself injections at home and miss a dose, call your doctor right away.
This is a plain-language summary of heparin's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store at room temperature, away from heat and light.
Side Effects (from patient reports)
Based on 12,966 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for heparin, by number of reports
- Low platelets caused by heparin
Low platelets caused by heparin
1,207 reports
- Feeling sick to your stomach
Feeling sick to your stomach
712 reports
- Allergic reaction to the medicine
Allergic reaction to the medicine
603 reports
- Throwing up
Throwing up
571 reports
- Low blood pressure
Low blood pressure
553 reports
- Difficulty breathing
Difficulty breathing
518 reports
- Fever 465
Fever
465 reports
- Low platelet count 458
Low platelet count
458 reports
- Blood clot in the lungs 457
Blood clot in the lungs
457 reports
- Blood infection 452
Blood infection
452 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 heparin 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 heparin sits
heparin has more FDA adverse-event reports than 45% 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 heparin; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 12,966 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
12,966
Reports Mentioning Death
2,519
19.4% of reports — not proof of cause
Hospitalization Reports
5,169
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | HEPARIN-INDUCED THROMBOCYTOPENIA | 1,207 |
| 3 | NAUSEA | 708 |
| 5 | DRUG HYPERSENSITIVITY | 603 |
| 6 | VOMITING | 572 |
| 7 | HYPOTENSION | 547 |
| 8 | DYSPNOEA | 519 |
| 9 | PYREXIA | 465 |
| 10 | THROMBOCYTOPENIA | 458 |
| 11 | PULMONARY EMBOLISM | 457 |
| 12 | SEPSIS | 452 |
| 13 | ABDOMINAL PAIN | 449 |
| 14 | ANAEMIA | 440 |
| 15 | THROMBOSIS | 406 |
| 16 | CONDITION AGGRAVATED | 368 |
| 17 | DEATH | 364 |
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
Heparin can cause serious bleeding, which can be fatal. It can also cause a severe reaction called heparin-induced thrombocytopenia (HIT), where your body attacks your own platelets. Make sure your doctor knows if you have ever had HIT. Using the wrong strength of heparin can also cause fatal bleeding.
Known Drug Interactions
7.2 Platelet Inhibitors Drugs such as NSAIDS (including salicylic acid, ibuprofen, indomethacin, and celecoxib), dextran, phenylbutazone, thienopyridines, dipyridamole, hydroxychloroquine, glycoprotein IIb/IIIa antagonists (including abciximab, eptifibatide, and tirofiban), and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.
Mechanism: Heparin thins the blood, and ibuprofen stops blood cells called platelets from sticking together. Using them together significantly increases your risk of dangerous bleeding.
What to do: Use this combination with extreme caution. Watch for signs of unusual bruising or bleeding and tell your doctor immediately if they occur.
7.2 Platelet Inhibitors Drugs such as NSAIDS (including salicylic acid, ibuprofen, indomethacin, and celecoxib), dextran, phenylbutazone, thienopyridines, dipyridamole, hydroxychloroquine, glycoprotein IIb/IIIa antagonists (including abciximab, eptifibatide, and tirofiban), and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.
Mechanism: Both drugs affect how your blood clots, with one thinning the blood and the other stopping platelets from clumping. This combination makes it much easier for you to bleed or bruise.
What to do: Use these medicines together only with caution. Your healthcare provider should monitor you closely for any signs of bleeding.
7.2 Platelet Inhibitors Drugs such as NSAIDS (including salicylic acid, ibuprofen, indomethacin, and celecoxib), dextran, phenylbutazone, thienopyridines, dipyridamole, hydroxychloroquine, glycoprotein IIb/IIIa antagonists (including abciximab, eptifibatide, and tirofiban), and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.
Mechanism: Hydroxychloroquine can interfere with how blood cells stick together to stop bleeding. When taken with a blood thinner like heparin, it increases the chance of serious bleeding.
What to do: Use this combination with caution. Be sure to report any unusual bleeding or bruising to your doctor right away.
7.2 Platelet Inhibitors Drugs such as NSAIDS (including salicylic acid, ibuprofen, indomethacin, and celecoxib), dextran, phenylbutazone, thienopyridines, dipyridamole, hydroxychloroquine, glycoprotein IIb/IIIa antagonists (including abciximab, eptifibatide, and tirofiban), and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.
Mechanism: Both drugs make it harder for your blood to clot, which increases the risk of bleeding. Indomethacin stops platelets from sticking together, while heparin thins the blood.
What to do: Use this combination with caution. Your doctor should watch closely for any signs of bleeding.
7.2 Platelet Inhibitors Drugs such as NSAIDS (including salicylic acid, ibuprofen, indomethacin, and celecoxib), dextran, phenylbutazone, thienopyridines, dipyridamole, hydroxychloroquine, glycoprotein IIb/IIIa antagonists (including abciximab, eptifibatide, and tirofiban), and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.
Mechanism: These drugs both interfere with how your blood clots, making it more likely that you will bleed. Dipyridamole stops blood cells from clumping together while heparin works as a blood thinner.
What to do: Use these medications together with caution. Your healthcare provider should monitor you for bleeding risks.
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 do if I experience bleeding while taking heparin?
Can I take other medications with heparin?
How often will my blood be tested while taking heparin?
What is heparin-induced thrombocytopenia (HIT)?
Can heparin be used to prevent blood clots during pregnancy?
What should I avoid while taking heparin?
How long will I need to take heparin?
What are the symptoms of a blood clot?
Is there a reversal agent for heparin?
What if I have a known allergy to pork products?
What are the common side effects of heparin?
Does heparin interact with other medications?
What drug class is heparin?
Is heparin safe during pregnancy?
Has heparin been recalled?
Is heparin currently in shortage?
Active Recalls
Microbial Contamination of Sterile Products; out of limit results obtained for endotoxin testing.
Baxter Healthcare Corporation
Related Medications in Unfractionated Heparin
Other drugs grouped near heparin - same-class peers and common alternatives.
apixaban
Eliquis
Apixaban (Eliquis) is a medicine that helps prevent blood clots.
Compare with heparin →
aspirin
Bayer, Ecotrin
Aspirin is a common medicine used to relieve minor pain.
Compare with heparin →
cilostazol
Pletal
Cilostazol is a medicine that helps improve walking distance in people with leg pain due to poor circulation.
Compare with heparin →
clopidogrel
Plavix
Clopidogrel is a drug that helps to prevent blood clots.
Compare with heparin →
dabigatran
Pradaxa
Dabigatran (Pradaxa) is a drug that helps to prevent blood clots from forming.
Compare with heparin →
Medication Guides
Understanding Drug Interactions
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FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for heparin
The FDA label for heparin (sold under brand names such as Heparin Sodium) classifies it as a prescription-only medication in the Unfractionated Heparin class. Heparin is used to prevent and treat blood clots in your veins and lungs. Official labeling lists 4 commonly reported side effects, including Bleeding, Irritation at the injection site, Allergic reactions.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 12,966 voluntary reports. The database also lists 20 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $2.17.
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 (currently 1 recall record on file), 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 26, 2025
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