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A DOAC Deep Dive: Apixaban
Updated January 2020
For the past several decades, warfarin has been the go-to anticoagulant (sometimes called a blood thinner), but newer treatments have emerged in the form of direct oral anticoagulants (DOACs). DOACs are as effective and safer than warfarin, especially with regard to serious bleeding episodes. DOACs include apixaban, betrixaban, dabigatran, edoxaban, and rivaroxaban.
Here’s an inside look at apixaban.
What is it?
Apixaban (Eliquis®), is an anticoagulant that reduces a patient’s risk of developing a blood clot, which can cause deep vein thrombosis (DVT), pulmonary embolism (PE), and stroke from atrial fibrillation (Afib). Apixaban comes in a tablet form and should be taken twice a day. Patients are generally prescribed 5 mg or 2.5 mg doses, which can be taken with or without food. The FDA first approved the drug in December 2012 and then signed off on a generic formulation in December 2019.
How does it work?
Apixaban is a direct factor Xa inhibitor. “The factor Xa inhibitors interrupt the process that allows blood to clot, known as the clotting cascade. They bind to factor Xa and stop it from continuing the clotting process,” explained John Fanikos, RPh, MBA, Director of Pharmacy Services for Brigham and Women’s Hospital.
Interrupting the clotting cascade ultimately stops a structure called fibrin from forming. Fibrin creates a weblike structure that catches blood platelets and other molecules, which then bind together to form a blood clot.
Apixaban vs. Warfarin
Apixaban is just as effective, if not more so, than warfarin.
“Apixaban has been shown to cause less major bleeding in patients compared to warfarin,” explained Fanikos, citing the ARISTOTLE trial.
In patients with Afib, apixaban has been shown to be better than warfarin at reducing the risk of stroke. It also causes less bleeding.
The ARISTOTLE trial was a multicenter, double-blind, comparative trial. The trial randomized 18,201 patients with nonvalvular Afib to take apixaban or warfarin. After following up with these patients, researchers found that apixaban was superior to warfarin in preventing strokes and was associated with less major bleeding.
For patients with DVT or PE, apixaban has been shown to be just as effective as warfarin in preventing blood clots, but has a significantly lower risk of bleeding. This was demonstrated in the AMPLIFY trial.
The AMPLIFY trial was a phase III, randomized, double-blind trial. Patients were randomized to apixaban or warfarin. While the two drugs showed similar rates of recurrent blood clots, fewer patients on apixaban had a major bleeding event compared to patients on warfarin.
What are the risks?
As with all anticoagulants, bleeding is the biggest risk associated with apixaban. Patients must be careful to avoid injuries that may cause major bleeding events. Injuries to the head can be especially dangerous.
“Patients who are at risk for head injury, such as those who play sports, really need to be careful about their bleeding risk,” remarked Fanikos.
Outside of major bleeds, patients may also experience gum bleeds, nosebleeds, increased bruising, bleeding around the eyes, and other forms of minor bleeding. In the event of major or life-threatening bleeding, apixaban can be reversed with an antidote called andexanet alfa (Andexxa®).
It’s important for patients to continue taking apixaban as prescribed and it should never be discontinued without guidance from the prescribing provider. Discontinuing apixaban increases a patient’s chance of developing a blood clot.