Drug vs. Drug

Coumadin vs Heparin: Main Differences and Similarities

By | May 29, 2019

Coumadin (warfarin) and heparin are two anticoagulant medications that can help treat and prevent blood clots. As anticoagulants, they work as “blood thinners” to ultimately prevent strokes and heart attacks. Although their effects are similar, they work in different ways. We’ll go over their differences and similarities here.


Coumadin is the brand name for warfarin. It works by blocking the effects of vitamin K and decreasing the production of blood clots. Coumadin is approved to prevent and treat blood clots in the veins (deep vein thrombosis, DVT) and the lungs (pulmonary embolism, PE). It can also treat blood clots that occur from atrial fibrillation, a potentially serious heart condition.

Coumadin is available as a generic and comes in oral tablets with strengths of 1 mg, 2 mg, 2.5 mg, 3 mg, 4 mg, 5 mg, 6 mg, 7.5 mg, and 10 mg. Dosing for Coumadin is highly individualized and based on a person’s response to the medication.

Those who take Coumadin have to make routine office visits to monitor the drug’s effects. At each visit, the doctor will use a blood test that measures a value called INR to ensure the medication is working correctly.


Heparin is one of the oldest known drugs approved in 1939 by the FDA. It can be used to treat DVTs and PEs as well as blood clots from atrial fibrillation. Because of its short half-life, it can also prevent blood clots during heart surgeries, blood transfusions, and dialysis procedures.

Heparin is administered by a healthcare professional as an IV (intravenous) or subcutaneous (under the skin) injection in varying strengths. Dosing depends on the condition being treated as well as other individual factors.

Like Coumadin, heparin needs to be monitored closely to ensure that it’s working properly. Rarely, heparin can also cause Heparin Induced Thrombocytopenia, a serious condition marked by an abnormal decrease in platelets.

Coumadin vs Heparin Side by Side Comparison

Coumadin and heparin are similar drugs that can treat blood clots. While they have similar effects, they also have several differences. Their features can be found in the comparison table below.

Coumadin Heparin
Prescribed For
  • Treatment and prevention of DVT and PE
  • Treatment and prevention of blood clots due to atrial fibrillation and/or heart valve replacement
  • Prevention of complications such as stroke and heart attack
  • Treatment and prevention of DVT and PE
  • Treatment and prevention of blood clots due to atrial fibrillation and/or heart valve replacement
  • Treatment and prevention of blood clots after surgery
  • Prevention of blood clots during blood transfusions and dialysis
Drug Classification
  • Anticoagulant
  • Anticoagulant
  • Pfizer
Common Side Effects
  • Bleeding
  • Hemorrhage
  • Bleeding
  • Hemorrhage
  • Low platelet count
  • Heparin induced thrombocytopenia (HIT)
  • Injection site reaction
  • Elevated liver enzymes
Is there a generic?
Is it covered by insurance?
  • Varies according to your provider
  • Varies according to your provider
Dosage Forms
  • Oral tablet
  • Solution for injection
Average Cash Price
  • $43 per 100, 1 mg Jantoven tablet
  • $195.76 per 60 ml (500units/ml)
SingleCare Discount Price
Drug Interactions
  • CYP2C9 inhibitors (amiodarone, fluvastatin, etravirine, etc.)
  • CYP2C9 inducers (phenobarbital, rifampin, carbamazepine, etc.)
  • CYP1A2 inhibitors (acyclovir, famotidine, propranolol, etc.)
  • CYP1A2 inducers (montelukast, omeprazole, phenytoin, etc.)
  • CYP3A4 inhibitors (amlodipine, cimetidine, diltiazem, etc.)
  • CYP3A4 inducers (aprepitant, modafinil, bosentan, etc.)
  • Anticoagulants (dabigatran, heparin, etc.)
  • Antiplatelet agents (aspirin, clopidogrel, etc.)
  • NSAIDs (ibuprofen, ketorolac, diclofenac, etc.)
  • Selective serotonin reuptake inhibitors (citalopram, escitalopram, etc.)
  • Herbals (St. John’s Wort, gingko, garlic, etc.)
  • Antibiotics (amoxicillin, ciprofloxacin, etc.)
  • Antifungals (ketoconazole, fluconazole, etc.)
  • Anticoagulants (dabigatran, warfarin, etc.)
  • Antiplatelet agents (aspirin, clopidogrel, etc.)
  • Antiplatelet agents (aspirin, clopidogrel, etc.)
  • NSAIDs (ketorolac, ibuprofen, etc.)
  • Antihistamines (diphenhydramine, fexofenadine, etc.)
  • Tetracyclines (doxycycline, minocycline, etc.)
  • Hydroxychloroquine
  • Dipyridamole
  • Digoxin
  • Dextran
  • Nicotine
  • Nitroglycerin
Can I use while planning pregnancy, pregnant, or breastfeeding?
  • Coumadin is in Pregnancy Category D. Therefore, it should not be taken during pregnancy. Consult a doctor regarding steps to take while planning pregnancy. Coumadin should not be taken while breastfeeding.
  • Heparin is in Pregnancy Category C. Fetal harm may occur although more research is needed. Consult a physician regarding taking Heparin while pregnant or breastfeeding.


Coumadin (warfarin) and heparin are two blood thinners than can help treat and prevent blood clots. Both medications can be used to treat and prevent deep vein thrombosis and pulmonary embolisms. Heparin can also be used during surgeries and other procedures to prevent blood clots.

Coumadin can be taken as a pill at home whereas heparin is administered as an injection by a healthcare professional. In this way, Coumadin may be more flexible to use since it does not need much supervision. However, Coumadin still needs to be monitored with routine visits to ensure it is working properly.

Because of heparin’s short half-life, it is usually preferred for short-term use and treatment for surgeries or procedures. Therefore, heparin may be preferred for its predictability. Still, it needs to be monitored with direct supervision during administration.

Both medications have rare but serious adverse effects such as bleeding or hemorrhaging. For this reason, they should also be avoided with other medications that can increase these effects. Depending on the condition being treated, both medications are equally as effective.

The information presented here is meant to be an brief comparison. Discuss these medications with your doctor for specific uses and instructions.