Heparin

Heparin interacts with the naturally occurring plasma protein, Antithrombin III, to induce a conformational change, which markedly enhances the serine protease activity of Antithrombin III, thereby inhibiting the activated coagulation factors involved in the clotting sequence, particularly Xa and IIa. Small amounts of heparin inhibit Factor Xa, and larger amounts inhibit thrombin (Factor IIa).

• Heparin Sodium Injection is indicated for: Prophylaxis and treatment of venous thrombosis and pulmonary embolism; Prevention of postoperative deep venous thrombosis and pulmonary embolism in patients undergoing major abdominothoracic surgery or who, for other reasons, are at risk of developing thromboembolic disease; Atrial fibrillation with embolization; Treatment of acute and chronic consumptive coagulopathies (disseminated intravascular coagulation); Prevention of clotting in arterial and cardiac surgery; Prophylaxis and treatment of peripheral arterial embolism. Anticoagulant use in blood transfusions, extracorporeal circulation, and dialysis procedures.ICD-10: I26.99, I48.91

• The use of Heparin Sodium Injection is contraindicated in patients with the following conditions: History of heparin-induced thrombocytopenia and heparin-induced thrombocytopenia and thrombosis [see Warnings and Precautions ( 5.3 )] ; Known hypersensitivity to heparin or pork products (e.g., anaphylactoid reactions) [see Adverse Reactions ( 6.1 )] ; In whom suitable blood coagulation tests, e.g., the whole blood clotting time, partial thromboplastin time, etc., cannot be performed at appropriate intervals (this contraindication refers to full-dose heparin; there is usually no need to monitor coagulation parameters in patients receiving low-dose heparin); An uncontrolled active bleeding state [see Warnings and Precautions ( 5.2 )] , except when this is due to disseminated intravascular coagulation.contraindicated

Recommended Adult Dosages: Therapeutic Anticoagulant Effect with Full-Dose Heparin † ( 2.4 ) † Based on 150 lb (68 kg) patient. Adjust dose based on laboratory monitoring. Deep Subcutaneous (Intrafat) Injection Use a different site for each injection Initial Dose 5,000 units by intravenous injection, followed by 10,000 to 20,000 units of a concentrated solution, subcutaneously Every 8 hours or Every 12 hours 8,000 to 10,000 units of a concentrated solution 15,000 to 20,000 units of a concentrated solution Intermittent Intravenous Injection Initial dose 10,000 units, either undiluted or in 50 to 100 mL of 0.9% Sodium Chloride Injection, USP Every 4 to 6 hours 5,000 to 10,000 units, either undiluted or in 50 to 100 mL of 0.9% Sodium Chloride Injection, USP Intravenous Infusion Initial dose 5,000 units by intravenous injection Continuous 20,000 to 40,000 units/24 hours in 1000 mL of 0.9% Sodium Chloride Injection, USP (or in any compatible solution) for infusion 2.1 Preparation for Administration Confirm the choice of the correct Heparin Sodium Injection vial to ensure that the 1 mL vial is not confused with a “catheter lock flush” vial or other 1 mL vial of incorrect strength [see Warnings and Precautions ( 5.1 )]. Confirm the selection of the correct formulation and strength prior to administration of the drug. To lessen this risk, the 1 mL vial includes a red cautionary statement. Read the cautionary statement and confirm that you have selected the correct medication and strength.

Fatal Medication Errors: Confirm choice of correct strength prior to administration ( 5.1 ) Hemorrhage: Fatal cases have occurred. Use caution in conditions with increased risk of hemorrhage ( 5.2 ) HIT and HITTS: Monitor for signs and symptoms and discontinue if indicative of HIT and HITTS ( 5.3 ) Benzyl Alcohol Toxicity: Do not use benzyl alcohol-preserved drugs in neonates and infants. ( 5.4 ) Monitoring: Blood coagulation tests guide therapy for full-dose heparin. Monitor platelet count and hematocrit in all patients receiving heparin ( 5.5 , 5.6 ) Hyperkalemia: Measure blood potassium in patients at risk of hyperkalemia before starting heparin therapy and periodically in all patients ( 5.9 ) 5.1 Fatal Medication Errors Do not use Heparin Sodium Injection as a “catheter lock flush” product. Heparin Sodium Injection is supplied in vials containing various strengths of heparin, including vials that contain a highly concentrated solution of 10,000 units in 1 mL. Fatal hemorrhages have occurred in pediatric patients due to medication errors in which 1 mL Heparin Sodium Injection vials were confused with 1 mL “catheter lock flush” vials. Carefully examine all Heparin Sodium Injection vials to confirm the correct vial choice prior to administration of the drug. 5.2 Hemorrhage Avoid using heparin in the presence of major bleeding, except when the benefits of heparin therapy outweigh the potential risks. Hemorrhage can occur at virtually any site in patients receiving heparin. Fatal hemorrhages have occurred.

The following clinically significant adverse reactions are described elsewhere in the labeling: Hemorrhage [see Warnings and Precautions ( 5.2 )] Heparin-Induced Thrombocytopenia and Heparin-Induced Thrombocytopenia and Thrombosis [see Warnings and Precautions ( 5.3 )] Risk of Serious Adverse Reactions in Infants Due to Benzyl Alcohol Preservative [ see Warnings and Precautions ( 5.4 ) ] Thrombocytopenia [see Warnings and Precautions ( 5.5 )] Heparin Resistance [see Warnings and Precautions ( 5.7 )] Hypersensitivity [see Warnings and Precautions ( 5.8 )] Hyperkalemia [see Warnings and Precautions ( 5.9 )] Most common adverse reactions are hemorrhage, thrombocytopenia, HIT and HITTS, injection site irritation, general hypersensitivity reactions, and elevations of aminotransferase levels. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Meitheal Pharmaceuticals Inc. at 1-844-824-8426 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Postmarketing Experience The following adverse reactions have been identified during post approval use of Heparin Sodium Injection. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Hemorrhage is the chief complication that may result from heparin therapy [see Warnings and Precautions ( 5.2 )] . Gastrointestinal or urinary tract bleeding during anticoagulant therapy may indicate the presence of an underlying occult lesion.

Pregnancy: Preservative-free formulation recommended. Limited human data in pregnant women. ( 8.1 ) Lactation: Advise females not to breastfeed. ( 8.2 ) Pediatric Use: Use preservative-free formulation in neonates and infants. ( 8.4 ) Geriatric Use: A higher incidence of bleeding reported in patients, particularly women, over 60 years of age. ( 8.5 ) 8.1 Pregnancy Risk Summary There are no available data on Heparin Sodium Injection use in pregnant women to inform a drug-associated risk of major birth defects and miscarriage. In published reports, heparin exposure during pregnancy did not show evidence of an increased risk of adverse maternal or fetal outcomes in humans. No teratogenicity, but early embryo-fetal death was observed in animal reproduction studies with administration of heparin sodium to pregnant rats and rabbits during organogenesis at doses approximately 10 times the maximum recommended human dose (MRHD) of 45,000 units/day [see Data ] . Consider the benefits and risks of Heparin Sodium Injection for the mother and possible risks to the fetus when prescribing Heparin Sodium Injection to a pregnant woman. If available, preservative-free Heparin Sodium Injection is recommended when heparin therapy is needed during pregnancy.

Metabolism

Absorption Heparin is not absorbed through the gastrointestinal tract and therefore administered via parenteral route. Peak plasma concentration and the onset of action are achieved immediately after intravenous administration.

Bleeding is the chief sign of heparin overdosage. Neutralization of Heparin Effect When clinical circumstances (bleeding) require reversal of the heparin effect, protamine sulfate (1% solution) by slow infusion will neutralize heparin sodium. No more than 50 mg should be administered, very slowly , in any 10-minute period. Each mg of protamine sulfate neutralizes approximately 100 USP heparin units. The amount of protamine required decreases over time as heparin is metabolized. Although the metabolism of heparin is complex, it may, for the purpose of choosing a protamine dose, be assumed to have a half-life of about 1/2 hour after intravenous injection. Because fatal reactions often resembling anaphylaxis have been reported with protamine, it should be given only when resuscitation techniques and treatment of anaphylactoid shock are readily available. For additional information consult the labeling of Protamine Sulfate Injection.

• Feb 22, 1972NDANDA017029Fresenius Kabi Usa
• Mar 22, 1972NDANDA017037Hikma
• Feb 10, 1978NDANDA017651Fresenius Kabi Usa
• Apr 28, 1982NDANDA018609Baxter Hlthcare
• Jan 31, 1984NDANDA018916Hospira
• Mar 27, 1985NDANDA019339Hospira
• Jul 20, 1992NDANDA019952B Braun
• Jul 20, 1992NDANDA019953B Braun

1. 1Heparin-induced Thrombocytopenia1,2849.3%
2. 2Drug Ineffective1,2278.9%
3. 3Off Label Use7315.3%
4. 4Nausea7285.3%
5. 5Drug Hypersensitivity6254.5%
6. 6Vomiting5924.3%
7. 7Hypotension5634.1%
8. 8Dyspnoea5373.9%
9. 9Pulmonary Embolism4953.6%
10. 10Pyrexia4873.5%
11. 11Sepsis4783.5%
12. 12Thrombocytopenia4713.4%
13. 13Anaemia4693.4%
14. 14Abdominal Pain4663.4%
15. 15Thrombosis4343.1%

Recent PubMed references pinned to Heparin as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Implementation of a clinical decision support tool to improve the adequate prescription of low-molecular-weight heparins in non-surgical patients.
  PloS one · 2026 · van Gosliga F, Pals D, van Ojik A, et al.
  PMID 42258514DOI 10.1371/journal.pone.0350017
• Thromboinflammatory and Pharmacological Effects of Low-Molecular-Weight Heparins in Acute Venous Thromboembolism: An Integrated Clinical and In Silico Analysis.
  Medical sciences (Basel, Switzerland) · 2026 · Onar LC, Guner E, Dalkiran IO, et al.
  PMID 42201052DOI 10.3390/medsci14020260
• Heparin-Coated Tunneled Hemodialysis Catheters Improve Failure-Free Survival in ESRD.
  Medicina (Kaunas, Lithuania) · 2026 · Tasci V, Tekin AF, Tanrıkulu YE, et al.
  PMID 42195057DOI 10.3390/medicina62050804
• Comparison of safety and efficacy of lower-intensity versus standard unfractionated heparin infusion nomograms for extracranial venous thromboembolism in the neurological intensive care unit.
  Clinical neurology and neurosurgery · 2026 · Hakoun AM, Gupta M, Dhar R, et al.
  PMID 42190494DOI 10.1016/j.clineuro.2026.109512
• Taking the 'HIT' (Heparin-induced thrombocytopenia) - Balancing Local Testing with Delayed Central Results.
  Irish medical journal · 2026 · Daly D, Fleming N, Murphy B, et al.
  PMID 42179217
• Activated partial thromboplastin time and hemorrhagic events in adults undergoing venovenous extracorporeal membrane oxygenation.
  The International journal of artificial organs · 2026 · O'Brien SK, Roberts RJ, Rosovsky RP, et al.
  PMID 42175637DOI 10.1177/03913988261445016
• Glycoprotein biosensor boosted by signal amplification of heparin polysaccharide and insights into glycan-lectin recognition.
  Mikrochimica acta · 2026 · Li L, Qu K, Gao X, et al.
  PMID 42174235DOI 10.1007/s00604-026-08135-y
• Optimizing Venous Thromboembolism Prophylaxis in Burn Patients Using Enoxaparin Through PBPK Modeling.
  CPT: pharmacometrics & systems pharmacology · 2026 · Mim SR, Yellepeddi VK, Azeredo FJ, et al.
  PMID 42150550DOI 10.1002/psp4.70265

The 10 most recently updated of 1,752 ClinicalTrials.gov registrations naming Heparin as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• PLATELET Function Assay With Flow Imaging on ImageSTREAM Cytometer
  Completed · Observational · 31 enrolled · Centre Hospitalier Universitaire, Amiens
  NCT04842760updated 2026-06-12
• Balloon Aortic Valvuloplasty Performed Without Heparin to Decrease Vascular and Bleeding Complications of the Procedure
  Terminated · Phase 4 · Interventional · 94 enrolled · University Hospital, Montpellier
  NCT01823393updated 2026-06-12
• Emulation of the RECORD3 Trial Using Healthcare Claims Data
  Active not recruiting · Observational · 149,248 enrolled · Brigham and Women's Hospital
  NCT07599384updated 2026-06-11
• Replication of the RECORD1 Anticoagulant Trial in Healthcare Claims Data
  Active not recruiting · Observational · 89,215 enrolled · Brigham and Women's Hospital
  NCT05083455updated 2026-06-11
• Prevention of Postpartum Venous Thromboembolism in Women at Intermediate Risk
  Recruiting · Phase 4 · Interventional · 2,400 enrolled · University Hospital, Brest
  NCT06845423updated 2026-06-10
• Antithrombotic Treatment Strategies in Cervical Artery Dissection
  Not yet recruiting · Interventional · 1,100 enrolled · University Department of Geriatric Medicine FELIX PLATTER
  NCT07639892updated 2026-06-10
• The PEERLESS II Study
  Recruiting · Interventional · 1,200 enrolled · Inari Medical
  NCT06055920updated 2026-06-10
• PDS01ADC in Combination With Hepatic Artery Infusion Pump (HAIP) and Systemic Therapy for Subjects With Metastatic Colorectal Cancer, Intrahepatic Cholangiocarcinoma, or Metastatic Adrenocortical Carcinoma
  Recruiting · Phase 2 · Interventional · 70 enrolled · National Cancer Institute (NCI)
  NCT05286814updated 2026-06-10
• Baseline Assessment of Skin Resident Memory T Cells in Healthy Unvaccinated Participants
  Not yet recruiting · Interventional · 40 enrolled · Institute of Tropical Medicine, Belgium
  NCT07636551updated 2026-06-09
• Characterization of the IFN-I Response in Subjects Who Experienced Severe or Mild Forms of COVID-19
  Recruiting · Interventional · 134 enrolled · Hospices Civils de Lyon
  NCT06703034updated 2026-06-09

Frequently asked questions

How does Heparin work?

Heparin interacts with the naturally occurring plasma protein, Antithrombin III, to induce a conformational change, which markedly enhances the serine protease activity of Antithrombin III, thereby inhibiting the activated coagulation factors involved in the clotting sequence, particularly Xa and IIa. Small amounts of heparin inhibit Factor Xa, and larger amounts inhibit thrombin (Factor IIa).

What is Heparin used for?

According to FDA labeling, Heparin carries indications including: Heparin Sodium Injection is indicated for: Prophylaxis and treatment of venous thrombosis and pulmonary embolism; Prevention of postoperative deep venous thrombosis and pulmonary embolism in patients undergoing major abdominothoracic surgery or who, for other reasons, are at risk of developing thromboembolic disease; Atrial fibrillation with embolization; Treatment of acute and chronic consumptive coagulopathies (disseminated intravascular coagulation); Prevention of clotting in arterial and cardiac surgery; Prophylaxis and treatment of peripheral arterial embolism. Anticoagulant use in blood transfusions, extracorporeal circulation, and dialysis procedures.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Heparin?

Heparin is classified as Heparin group, Heparins or heparinoids for topical use, Other ophthalmologicals, Antithrombin Activators, Thrombin Inhibitors, Decreased Coagulation Activity, Decreased Coagulation Factor Activity.

What are the brand names for Heparin?

Heparin is marketed under brand names including Defencath.

What are the contraindications for Heparin?

Heparin labeling lists contraindications including: The use of Heparin Sodium Injection is contraindicated in patients with the following conditions: History of heparin-induced thrombocytopenia and heparin-induced thrombocytopenia and thrombosis [see Warnings and Precautions ( 5.3 )] ; Known hypersensitivity to heparin or pork products (e.g., anaphylactoid reactions) [see Adverse Reactions ( 6.1 )] ; In whom suitable blood coagulation tests, e.g., the whole blood clotting time, partial thromboplastin time, etc., cannot be performed at appropriate intervals (this contraindication refers to full-dose heparin; there is usually no need to monitor coagulation parameters in patients receiving low-dose heparin); An uncontrolled active bleeding state [see Warnings and Precautions ( 5.2 )] , except when this is due to disseminated intravascular coagulation.. Always consult the full prescribing information and a clinician.