Anticoagulants: Uses, common brands, and safety info

Anticoagulants are the category of medications commonly referred to as blood thinners. As the treatment for blood clots, these medications have a critical role in saving lives from conditions such as pulmonary emboli (blood clots in the lung) and heart attacks and reducing disability from strokes. Used in a preventive manner, anticoagulant medications are also of great importance in reducing the risk of blood clots. Inhibiting our body’s ability to clot (coagulation) carries significant risk, so understanding the benefits and risks of anticoagulants is crucial. We will discuss the names and costs of common anticoagulants, along with their uses and risks.

Other anticoagulants

• Bivalirudin 

• Desirudin

• Betrixaban

• Edoxaban

• Alteplase

• Reteplase

What are anticoagulants?

Anticoagulants are a broad category of medications that work by helping the body to dissolve clots that have formed and by reducing the likelihood of the body forming new clots. For more than 60 years, heparin and warfarin have been used as blood thinners, and more recently, the direct oral anticoagulant medications, like Eliquis and Xarelto, have made blood thinning more convenient. Some anticoagulants are taken orally in pill form and others must be injected under the skin or in a vein. They are commonly used both in the hospital and in outpatient medicine.

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How do anticoagulants work?

The body creates a blood clot by utilizing a cascade of enzyme reactions between clotting factors that trigger one another, a domino effect that ultimately leads to a clot. Anticoagulants block that chain reaction, different members of the drug class doing so at different points. Platelet blood cells also contribute risk of blood clots and are another target for anticoagulation.

What are anticoagulants used for?

• Venous thrombosis and thromboembolism (blood clot within the venous system)

• Arterial thrombosis and thromboembolism (blood clot within the arterial system)

• Deep vein thrombosis, also known as DVT (blood clot in the deep veins)

• Pulmonary embolism (blood clot in the lung)

• Myocardial infarction (heart attack)

• Coronary artery disease (blockages within the blood vessels supplying the heart)

• Atrial fibrillation (heart arrhythmia)

• Non-hemorrhagic stroke (stroke not related to bleeding in the brain)

• Transient ischemic attack (stroke symptoms without permanent brain tissue damage)

• Prevention of blood clots in individuals at an increased risk, such as those with artificial heart valves, hospitalized patients, patients after joint replacements, individuals with genetic tendencies for excess blood clots, and those who have experienced serious blood clots in the past

RELATED: Do you have to take blood thinners for AFib?

Types of anticoagulants

Heparins

To reduce clotting, unfractionated heparin and the fractionated low molecular weight heparins, Lovenox and Fragmin, enhance the action of antithrombin to inactivate factor Xa, while unfractionated heparin also uses antithrombin to inhibit thrombin. Arixta consists of a portion of the heparin molecule and also inactivates factor Xa.

Heparins can be administered intravenously or via an injection under the skin. It is typically used in hospitals to treat a variety of conditions related to blood clots and to prevent clots in at-risk patients. Intravenous heparin requires frequent blood monitoring to ensure the proper amount of blood thinning. Lovenox, Fragmin, and Arixtra are given as injections, making them useful in similar ways to heparin for both hospitalized and outpatient individuals. Regular blood tests can be done to monitor Lovenox or Fragmin therapy but are often unnecessary.

Direct thrombin inhibitors

Direct thrombin inhibitors, like Pradaxa, also limit thrombin’s clotting activity but do so directly, unlike the indirect mechanism of heparins. Pradaxa comes only in pill form, and it is used to prevent stroke in patients with atrial fibrillation and to treat and prevent blood clots within the venous system. The dosage of Pradaxa is not monitored or adjusted with frequent blood tests.

Direct Factor Xa inhibitors

As the name implies, direct Factor Xa inhibitors, like Eliquis and Xarelto, limit Factor Xa activity, leading to less thrombin and consequently less blood clotting. These oral drugs are often used to prevent stroke in patients with atrial fibrillation, as well as to treat and prevent venous system blood clots. Frequent blood tests are not necessary to adjust these agents’ dosing.

Vitamin K antagonists

Warfarin takes a different route to stop the clotting cascade; this drug is a vitamin K antagonist, blocking the action of vitamin K in the liver where it assists in the manufacturing of clotting factors. Having been used for many decades, this medicine has numerous indications for its use. Available as an oral medication only, warfarin can be used to prevent strokes in patients with atrial fibrillation and to treat and prevent blood clots within the venous system and the heart, including heart valves.

The drug interacts with a myriad of other medications, and its activity is also affected by dietary vitamin K intake, commonly found in leafy vegetables.

Multiple factors contribute to determining what dose of warfarin will be effective. Therefore, close monitoring of the blood test International Normalized Ratio (INR) is necessary for safe and effective warfarin usage. The blood test is often done multiple times per week initially and may be gradually reduced to monthly if a stable dose is achieved.

Tissue plasminogen activators

Alteplase and reteplase are examples of tissue plasminogen activators or thrombolytics, a powerful class of anticoagulants that come in intravenous form. They break up blood clots by increasing plasmin levels, which dissolves blood clots. These drugs are used in emergency rooms and hospitals to treat strokes, heart attacks, and other severe blood clots.

Platelet inhibitors

In addition to the series of enzyme reactions used in blood clotting, circulating blood cells called platelets assist in the formation of clots. Platelet inhibitors, such as aspirin, Plavix, and Brilinta, have an anticoagulant effect by reducing the activity of platelets. These pills can be used to treat and prevent heart attacks and strokes by reducing blood clotting within coronary and carotid arteries. The combination tablet aspirin with extended-release dipyridamole is used for stroke prevention.

Who can take anticoagulants?

Adults

Depending on their other health conditions, men and women can both use anticoagulants if the benefits of blood thinning outweigh the risks of bleeding. Assessing for any ongoing bleeding, any history of excess bleeding, and any risk factors for excess bleeding is worthwhile before initiating anticoagulant therapy. Women of reproductive age require particular caution in regards to certain blood thinners.

Seniors

Seniors experience a higher prevalence of health conditions related to blood clots and so more often need anticoagulants. Unfortunately, seniors are also at a higher risk of bleeding complications. Longer medication lists and coinciding medical conditions for seniors are other factors needing consideration when starting a senior on a blood thinner.

Children

Blood clots can occur within the pediatric population. Children's dosages of heparins and coumadin are based on their weight. Some of the newer anticoagulants, such as Xarelto, have been studied in and can be used for children. However, some medications, like Eliquis and Pradaxa, have not been adequately studied in children yet.

Are anticoagulants safe?

Anticoagulant recalls

• Heparin compounded product recall (August 2020)

• Eliquis recall (February 2018)

• Enoxaparin recall (February 2021)

Anticoagulant restrictions

A black box warning from the FDA exists for the following anticoagulants:

• Warfarin regarding bleeding risk

• Eliquis, Pradaxa, and Xarelto regarding spinal hematoma risk and also regarding premature discontinuation leading to clotting

• Lovenox, Fragmin, and Arixtra regarding spinal hematoma risk

• Plavix regarding reduced effectiveness in certain patients

Other restrictions include:

• People who have had hypersensitivity reactions to the anticoagulant or related anticoagulants should not take it again. A history of hypersensitivity to pork products can preclude heparin, Lovenox, and Fragmin use.

• Avoid anticoagulant use in the setting of active major bleeding.

• Individuals with a history of heparin-induced thrombocytopenia (low platelets) should not use heparin or Fragmin or often Lovenox, due to the potential for recurrence of this life-threatening reaction to heparins.

• Avoid warfarin in patients who cannot comply with frequent blood tests and in women with threatened abortion, eclampsia, or pre-eclampsia.

• Avoid aspirin and aspirin-dipyridamole ER in individuals with an active stomach ulcer, G6PD, or aspirin-induced asthma.

• Caution should be taken before using anticoagulants if active bleeding, significant bleeding risk, severe high blood pressure, low platelet counts, or significant liver or kidney disease are ongoing, as well as in seniors, children, pregnancy, and women of reproductive age.

• Caution with or avoidance of anticoagulants is typical if one has had recent surgery, a spinal tap, or spinal anesthesia.

• Warfarin use also requires caution in patients with a history of congestive heart failure, diabetes mellitus, vasculitis, polycythemia, protein C or S deficiency, indwelling catheters, smoking habit change, acute infection, altered intestinal flora, and heparin-induced low platelets, as well as in patients with debility.

• Use Eliquis, Xarelto, or Pradaxa with caution in patients with antiphospholipid syndrome or artificial heart valves and if Eliquis is used preventively for patients weighing less than 60 kg.

• Plavix also requires caution if used in the setting of gastrointestinal or eye diseases.

• Aspirin and aspirin-dipyridamole ER use also require caution if there is an ongoing viral illness, increased intracranial pressure, or an intracranial lesion. Aspirin-dipyridamole ER necessitates caution in the setting of low blood pressure and coronary artery disease.

• Brilinta also requires particular caution for individuals with a history of certain heart arrhythmias or heart bypass surgery.

• Lovenox, Fragmin, and Arixtra use also require caution if used in the settings of diabetic retinopathy and acute endocarditis, as well as in both obese and underweight individuals. Latex allergy is a potential concern with Arixtra.

RELATED: Are blood thinners and alcohol safe to mix?

Can you take anticoagulants while pregnant or breastfeeding?

Use Heparin, Lovenox, Fragmin, aspirin, Plavix, and Brilinta with caution in pregnancy and breastfeeding. Avoid warfarin in pregnancy unless absolutely necessary, but it can be used during breastfeeding. Avoid Eliquis, Xarelto, and Pradaxa in pregnancy and breastfeeding due to the lack of clinical trials on their use.

RELATED: How to avoid blood clots during pregnancy

Are anticoagulants controlled substances?

Anticoagulants are not controlled substances.

Common anticoagulants side effects

The following are some common side effects among anticoagulants. Patients should consult a healthcare provider for medical advice regarding their specific medication and its side effects.

• Bleeding (including bleeding gums and nosebleeds)

• Skin or tissue damage and calcification

• Allergic reaction

• Liver or kidney damage

• Anemia or low platelet counts

• Abdominal pain, nausea, vomiting, or diarrhea

• Headache, fatigue, or malaise

• Cold intolerance

• Dizziness, low blood pressure, numbness, or passing out

• Osteoporosis (thinning of the bones)

• Stomach ulcer

• Heart arrhythmia

How much do anticoagulants cost?

While the expense of older anticoagulants, like warfarin and aspirin, are low, the newer generations of anticoagulants have significant cost burdens. Eliquis, Xarelto, Pradaxa, Plavix, and Brilinta can all cost over $500 for a one-month supply. SingleCare has discount coupons available for these and other anticoagulants, and a SingleCare discount card can help you to save on your prescriptions.