Eliquis (apixaban) is a widely prescribed anticoagulant medication designed to prevent harmful blood clots. It belongs to a class of drugs known as direct-acting oral anticoagulants (DOACs) or Factor Xa inhibitors. These medications are commonly used to reduce the risk of stroke in individuals with atrial fibrillation, and to treat or prevent deep vein thrombosis (DVT) and pulmonary embolism (PE). Eliquis works by blocking a specific protein called Factor Xa, which plays a significant role in blood clotting.
Why Reversal is Needed
While Eliquis is highly effective in preventing dangerous blood clots, its function as a blood thinner also introduces the risk of major or life-threatening bleeding. This risk is particularly concerning in situations such as severe trauma, emergency surgical procedures, or instances of spontaneous internal bleeding, like an intracranial hemorrhage or gastrointestinal bleeding. In these scenarios, the anticoagulant effect of Eliquis can hinder the body’s natural ability to stop bleeding.
Rapidly reversing the anticoagulant effect is necessary for controlling bleeding and preserving a patient’s life. If the drug’s effects are not quickly neutralized, even a minor injury could lead to extensive blood loss. For example, a head injury that might cause a small bruise in someone not on blood thinners could result in more severe bleeding in the brain for a person taking Eliquis. Therefore, the availability of a specific reversal agent is urgently needed in unpredictable and serious medical emergencies.
The Antidote: Andexxa
Andexxa (andexanet alfa) is the specific and currently only approved antidote for reversing the anticoagulant effects of Eliquis (apixaban) and Xarelto (rivaroxaban). It was approved by the FDA in May 2018 for use in patients experiencing life-threatening or uncontrolled bleeding while on these Factor Xa inhibitors. Andexanet alfa is a modified recombinant Factor Xa protein.
Andexxa acts as a “decoy” or “trap” for Eliquis. It binds to Eliquis in the bloodstream, effectively sequestering the drug and preventing it from inhibiting natural Factor Xa. This binding action allows the body’s own Factor Xa to become available again, restoring the normal blood clotting process. Additionally, Andexxa has been observed to bind to and inhibit Tissue Factor Pathway Inhibitor (TFPI), which further contributes to increased thrombin generation and clot formation.
Andexxa is administered intravenously, typically as an initial bolus (a rapid, single dose) followed by a continuous infusion over two hours. The specific dosage regimen, whether a low or high dose, depends on the strength of the last Eliquis dose taken and the time elapsed since that dose. For instance, if the last dose of apixaban was 5 mg or less, or if the timing is unknown but the dose was taken more than 8 hours ago, a low dose of Andexxa is used, consisting of a 400 mg intravenous bolus followed by a 480 mg infusion over two hours. If the apixaban dose was greater than 5 mg, or if the timing is unknown but the dose was taken less than 8 hours ago, a high dose of 800 mg bolus followed by a 960 mg infusion over two hours is recommended. This treatment leads to a rapid and substantial decrease in anti-Factor Xa activity, typically within two minutes of the bolus dose.
Important Considerations
While Andexxa offers a significant advancement in managing bleeding complications, its use comes with important considerations and potential risks. The primary concern is the increased risk of thromboembolic events, which are the formation of new blood clots. These can include serious conditions such as deep vein thrombosis, pulmonary embolism, myocardial infarction (heart attack), and ischemic stroke. This risk arises because Andexxa reverses the anticoagulant effect, thereby removing the protection against clot formation that Eliquis provided.
Other potential side effects include infusion-related reactions, which may manifest as flushing, a feeling of warmth, or discomfort at the injection site. Allergic reactions, though less common, can also occur, ranging from mild skin rashes to more severe anaphylaxis. Patients may also experience urinary tract infections and pneumonia. Medical professionals carefully weigh these risks against the immediate threat of uncontrolled bleeding, reserving Andexxa for life-threatening or uncontrolled hemorrhage.
Close monitoring of patients during and after Andexxa administration is important. Healthcare providers watch for signs and symptoms of new blood clots, cardiac arrest, or other ischemic events. It is also important to note that Andexxa is not a routine antidote and is exclusively administered in a hospital setting under specialized medical supervision. Resuming anticoagulant therapy as soon as medically appropriate after the bleeding is controlled is advised to mitigate the heightened risk of thrombosis.