For the past several decades, warfarin has been the go-to anticoagulant drug for doctors, but new treatments have emerged in the form of direct oral anticoagulants (DOACs). DOACs are considered as or more effective and safer than warfarin, especially in relation to serious bleeding episodes. These anticoagulants include apixaban, betrixaban, dabigatran, edoxaban, and rivaroxaban.
NATF is dedicated to offering readers a closer look at each DOAC in order to empower patients to make informed healthcare decisions. Here is an inside look at apixaban:
What is it?
Apixaban, also known as Eliquis, is an anticoagulant drug that is designed to reduce a patient’s risk of developing a blood clot, which can cause deep vein thrombosis (DVT), pulmonary embolism (PE), and stroke from atrial fibrillation. Apixaban comes in a tablet form and is meant to 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 drug was approved by the FDA in December 2012.
How does it work?
Apixaban is a direct factor Xa inhibitor, as are anticoagulants rivaroxaban, edoxaban, and betrixaban. They work by blocking a molecule called prothrombin from becoming thrombin. By doing this they interrupt the clotting cascade, which is the process through which blood clots form.
“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 web-like structure that catches blood platelets and other molecules, which then bind together and 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 when compared to warfarin,” explained Fanikos, citing the ARISTOTLE trial.
In patients with nonvalvular atrial fibrillation, apixaban has been shown to be better than warfarin at reducing a patient’s risk of developing a stroke. It also causes less bleeding.
The ARISTOTLE trial was a multicenter, double-blind, comparative trial. The trial randomized 18,201 patients with nonvalvular atrial fibrillation 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 venous thromboembolism (VTE) or blood clots, 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 take apixaban or warfarin. While the two drugs showed similar rates of recurrent VTE, 1.8% of patients on warfarin had a major bleeding event and only 0.6% of patients on apixaban had a major bleeding event.
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 bad.
“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.
For many patients, the lack of an antidote (to stop bleeding) for apixaban is a concern. They are often used to taking warfarin, which can be reversed with vitamin K administration. However, as the ARISTOTLE trial showed, bleeding is less likely to occur in patients with apixaban. Even with reversal options, bleeding on warfarin is still a major risk and treatment can only go so far.
Outside of major bleeds, patients may also experience gum bleeds, nose bleeds, increased bruising, bleeding around the eyes, and other forms of minor bleeding.
It’s important for patients to continue taking apixaban as prescribed and it should never be discontinued without guidance from the prescribing doctor. Discontinuing apixaban increases a patient’s chance of developing a blood clot.
Interested in learning more?
It’s important for patients to always consult with their healthcare provider before starting apixaban or any other DOAC. Only a healthcare provider can decide what treatment works best for an individual patient.
Talk to your doctor about what treatments are best for you.