Jennifer Lockie
Joliet Junior College
According to the American Heart Association, there are, at minimum, 2.7 million Americans currently diagnosed with atrial fibrillation (a-fib). This condition accounts for 15-20% of strokes. As a result, patients are prescribed an anticoagulation therapy to decrease this risk (What is atrial fibrillation, 2016). While warfarin has been the medication of choice for decades, new anticoagulation medications have been approved in recent years that may be more effective with less risk. One of the more recent medications approved is Eliquis (apixaban) (Cassavaugh & Stummer, 2014). Is Eliquis more beneficial for patients with nonvalvular a-fib compared to warfarin? Warfarin was authorized by the FDA in 1954 and Eliquis was authorized by the FDA in 2012. Both medications are used for the prevention of ischemic stroke in patients with nonvalvular a-fib. During a phase 3, double-blinded ARISTOTLE study, patients with nonvalvular a-fib and at least one additional risk factor for stroke were given either Eliquis 5mg BID or adjusted dose warfarin. Patients with two or more of the following risk factors were given Eliquis 2.5mg BID: weight of 60 kg or less, age of 80 years or more, or SCr of 1.5 mg/dL or greater. This study found that Eliquis was superior to warfarin in regards to reduction of stroke, systemic embolism and major bleeding. In regards to peptic ulcer disease and GI issues, neither Eliquis nor warfarin had an increased risk for development (Drug class review, 2013). Eliquis works by prohibiting factor Xa in the clotting sequence, which lowers the chance of blood clot formation (Cassavaugh & Stummer, 2014). This is an important distinction from warfarin as the mechanism of action does not require any special dietary considerations when taking Eliquis (Drug class review, 2013). Warfarin works by preventing the production of vitamin K-dependent clotting factors. These factors include anticoagulant proteins C and S as well as factors II, VII, IX, and X (Drug class review, 2013). Due to this mechanism of action, patients taking warfarin will have to monitor the amount of vitamin K-rich foods they consume. Some examples of these foods include green leafy vegetables, broccoli, spinach, Brussel sprouts, or kale; soybeans; coleslaw; kiwifruit; and tuna in oil. While these foods do not need to be eliminated from the patient’s diet, they will need to be consumed consistently. Increased ingestion of these foods may lower the effectiveness of warfarin, increasing the risk of blood clots and stroke (A Patient's Guide to Taking Warfarin, 2014). In normal circumstances, Eliquis does not require routine blood test monitoring to verify the therapeutic range, whereas warfarin requires consistent monitoring of PT/INR blood tests to verify therapeutic range and adjust the dosage as needed (Cassavaugh & Stummer, …show more content…
The INR is a specific mathematical calculation of the PT or prothrombin time. This test is used to monitor the efficacy of anticoagulation therapy. The therapeutic range for patients taking warfarin is an INR of 2.0 to 3.0 (Malarkey & McMorrow, 2012, p.526). If the patient’s INR is too low, then the medication is not reaching its therapeutic goal. If the INR results are too high, then the patient will be at an increased risk of bleeding. Factors that can modify the effectiveness of warfarin and increase/decrease the PT/INR include medications, alcohol, and foods containing vitamin K (A Patient's Guide to Taking Warfarin, 2014). If patients taking Eliquis experience increased bleeding or need surgery, the doctor may order a PT/INR or anti-factor Xa tests to gauge the patient’s coagulation factors (Guidelines for the Management of Anticoagulant, …show more content…
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