Coumadin vs. heparin: Differences, similarities, and which is better for you

Drug overview & main differences | Conditions treated | Efficacy | Insurance coverage and cost comparison | Side effects | Drug interactions | Warnings | FAQ

Anticoagulation therapy plays a key role in the management of serious conditions such as atrial fibrillation, venous thromboembolism, and mechanical heart valve placement. The anticoagulant medications Coumadin and heparin help manage and prevent the formation of blood clots which can be fatal in these conditions.

Vitamin K is a key component in the pathway to clot formation. It is required in the synthesis of active clotting factors II, VII, IX, and X. Once it is used in the synthesis of these blood clotting factors, vitamin K becomes “deactivated” and must be reactivated by vitamin K epoxide reductase complex 1 (VKORC1) in order to continue participating in the clot formation process. Coumadin inhibits a component of the VKOR complex and thereby contributes to the depletion of vitamin K in the body, which slows the body’s ability to form clots.

Heparin works by binding to the protein antithrombin III which subsequently inactivates thrombin and other clotting factors, most importantly factor Xa. These steps inhibit the conversion of fibrinogen to fibrin, a key step in clot formation. By slowing the formation of fibrin, heparin decreases clot formation in the body.

What are the main differences between Coumadin and heparin?

Coumadin is a prescription drug that is commonly referred to by its generic name, warfarin, or sometimes Jantoven. It is used to prevent the formation of blood clots in conditions such as atrial fibrillation, stroke, myocardial infarction, and venous thromboembolism. It is available as an oral tablet in a variety of doses ranging from 1mg to 10mg per tablet. While on Coumadin, patients must submit to regular prothrombin tests (PT) reported as an International Normalized Ratio (INR) to determine if a patient’s dose is therapeutically appropriate. Warfarin is typically not used in patients less than 4 months of age due to administration issues and the potential for undiscovered genetic factors which may affect sensitivity.

Heparin is a prescription drug that is most commonly used in the inpatient setting. It is used to prevent the formation of blood clots in conditions such as deep venous thrombosis, pulmonary embolism, and atrial fibrillation. It is also used to prevent clot formation during procedures involving the heart and blood vessels. Heparin is available in various solution forms for intravenous injections or infusions. There is a specific formulation of heparin intended only for intravenous line flushing to prevent clot formation in the line. This is called a heparin lock flush, and this formulation should not be used for any other purpose. Heparin can be used for patients of any age, but close monitoring is required.

Conditions treated by Coumadin and heparin

Coumadin is used to prevent and treat venous thromboembolism and pulmonary embolism as well as coagulation complications associated with atrial fibrillation and mechanical valve replacements. Coumadin is also used to prevent coagulation related complications which may follow a myocardial infarction or heart attack.

Heparin is also used to prevent and treat venous thromboembolism and pulmonary embolism as well as coagulation complications associated with atrial fibrillation. In addition, heparin is used to prevent coagulation in cardiovascular surgeries, blood transfusions, and dialysis procedures.

Is Coumadin or heparin more effective?

Coumadin and heparin have differences which give them each a valuable place in therapy, oftentimes in the same patient.

The elimination half-life and time to peak concentration are two of the most important clinical factors in determining how and when to use each drug. Coumadin reaches peak plasma levels from a single dose in about 4 hours, with an elimination half-life of about 40 hours. Because of several factors that can vary with each patient, it can take days to weeks to reach a therapeutic INR.  Heparin reaches peak plasma concentrations in 2 to 4 hours, with an elimination half-life of about 60-90 minutes.

The guidelines for the management of deep vein thrombosis (DVT) and pulmonary embolism for many patient types will recommend the initial use of heparin due to its quick onset. Therapeutic effectiveness is achieved by administering a loading dose followed by a maintenance dose. This is continued while Coumadin therapy is initiated, and until a patient’s INR is therapeutic. This can take 7-10 days. Heparin generally needs to be managed in an inpatient setting, but a patient may go home once they are transitioned to Coumadin.

Only a healthcare provider can determine what therapy, or combination of therapy, is appropriate for each patient. Providers must take into account many patient-specific factors, such as history of clotting events, age, previous treatment, and history of conditions such a heparin-induced thrombocytopenia.

Coverage and cost comparison of Coumadin vs. heparin

Most Medicare and commercial insurance plans cover Coumadin, and/or its generic version warfarin. The average retail cost of Coumadin can range from $80 to $120 dollars. You can get warfarin for around $10 with a SingleCare coupon.

Heparin is most often given in the hospital setting and is generally covered under Medicare Part B. For non-Medicare patients, it is covered by medical insurance when considered reasonable and necessary. A patient’s out of pocket cost will depend on several factors including whether they have met their deductible and if they have supplemental coverage. If a patient finds that their Heparin is not covered, they may download a coupon and pay as low as $45 for a prescription.

Common side effects of Coumadin and heparin

The most common side effects of both Coumadin and heparin is hemorrhage or severe bleeding. Some signs of hemorrhage can be hard to recognize, but a few of the more obvious signs include easy bruising, nosebleeds, bleeding in the gums, brown or rust-colored urine, and blood in the eye. If a patient is determined to be hemorrhaging, withdrawal from the drug is necessary, whether it is temporary or long term.

Heparin-induced thrombocytopenia (HIT) has been reported in 1-2% of patients given heparin. This severe drop in platelet count can lead to serious complications such as tissue necrosis and gangrene.

There are other complications and serious side effects from treatment with Coumadin or heparin. A physician or pharmacist can provide a complete list of side effects.

This may not be a complete list of adverse events. Please consult a doctor or pharmacist for a complete list.
Source: DailyMed (Coumadin), DailyMed (heparin).

Drug interactions of Coumadin vs. heparin

Coumadin is metabolized by cytochrome P450 enzymes, primarily the subtypes 2C9, 1A2, and 3A4. Inhibitors of these enzymes essentially increase Coumadin levels, therefore increasing a patient’s INR and increasing their risk of hemorrhage. Examples of these enzyme inhibitors include antifungals such as fluconazole, and the popular cholesterol drug, atorvastatin. Enzyme inducers will lower the levels of Coumadin, potentially making a patient’s INR subtherapeutic and increasing the chase of a thrombotic event. Examples of enzyme inducers include the anti-seizure medications carbamazepine and phenobarbital.

The effects of heparin can be potentiated by antiplatelet drugs like NSAIDs. Ibuprofen would be an example. Heparin’s effects can be decreased by interactions with common antibiotics such as doxycycline.

The following table is not an all-inclusive list of interactions. Your healthcare provider can provide a more comprehensive list and additional information on each interaction.

Warnings of Coumadin and heparin

Coumadin and heparin can each increase the occurrence of a hemorrhagic event. Certain drugs can increase the likelihood of this occurring. Patients on Coumadin must have their INR checked regularly. High intake of vitamin K, contained in many foods such as green leafy vegetables, may decrease the effectiveness of Coumadin. Patients should maintain a consistent daily intake of Vitamin K while on Coumadin in order to maintain a therapeutic INR. Coumadin is contraindicated in pregnancy.

Heparin-induced thrombocytopenia occurs in 1% to 2% of patients and is a serious event that leads to the destruction of platelets. This can lead to gangrene and skin necrosis if not caught in time.

Frequently asked questions about Coumadin vs. heparin

What is Coumadin?

Coumadin is an oral anticoagulant drug used in the treatment and prophylaxis of venous thrombosis and pulmonary embolism. It is also used to manage clotting events associated with atrial fibrillation and cardiac stent placement. It is taken by mouth typically once per day, and patients must have their INR monitored regularly to ensure their Coumadin dose is appropriate.

What is heparin?

Heparin is an anticoagulant drug given intravenously in a hospital setting. It is used in the treatment and prophylaxis of venous thrombosis and pulmonary embolism. It is also used to manage clotting events during cardiac and venous surgery procedures. Patients typically receive a loading dose followed by an infusion, which may last several days depending on the treatment.

Are Coumadin and heparin the same?

While Coumadin and heparin are both anticoagulant medications, they are not the same. Coumadin is an oral prescription drug mostly used in the outpatient setting, while heparin is an injectable drug typically used in the hospital setting.

Is Coumadin or heparin better?

Heparin’s onset of action is much faster than Coumadin but must be followed by a continuous infusion or frequent injections. Therefore, heparin can typically only be used in the hospital setting. Coumadin can take several days to become effective but is safe to be taken in the outpatient setting. Patients on Coumadin must subject to regular blood tests to ensure their INR is in the appropriate range.

Can I use Coumadin or heparin while pregnant?

Coumadin crosses the placenta in pregnant women and has been proven to have teratogenic effects. Coumadin is, therefore, contraindicated in pregnancy unless the patient has a mechanical heart valve or is at a very high risk for a thromboembolic event. Heparin can be given during pregnancy as it does not cross the placenta, however, most practitioners prefer low molecular weight heparin (LMWH) in pregnancy such as Lovenox (enoxaparin).

Can I use Coumadin or heparin with alcohol?

There is no contraindication to alcohol use for Coumadin or heparin. However, alcohol may affect hepatic function in some patients, causing the need for closer monitoring of INR when taking Coumadin.

What is the generic name for heparin?

Heparin is the generic name.