New Oral Anticoagulants for Atrial Fibrillation

Case 1A : A 68-year-old man with a past medical history of atrial fibrillation (AF), hypertension, and type 2 diabetes mellitus has been on anticoagulation therapy with warfarin for 6 years. The patient's target international normalized ratio (INR) is 2.0 to 3.0. The patient has been managed by a pharmacist-run anticoagulation clinic, and his recent warfarin doses and INR values are shown inTable 1. He has had no bleeding or thrombotic complications. His current medications include warfarin, metformin, lisinopril, and atorvastatin. The patient has recently read about the United States Food and Drug Administration (FDA) approvals of dabigatran etexilate and rivaroxaban and would like to know if he should be switched from warfarin to dabigatran.View this table:Table 1. INR Values for Patient in Case 1aCase 1B: After discussion with the cardiologist and pharmacist, the patient in Case 1A decided that he would like to switch to dabigatran etexilate. He and his referring cardiologist would like to know how to switch a patient from warfarin to dabigatran. Pertinent labs include a serum creatinine of 0.7 mg/dL (creatinine clearance 80 mL/min) and liver function tests within normal limits. His medications remain unchanged.Case 2: A 70-year-old, 70-kg woman with a past medical history of hypertension presented to the emergency department with signs and symptoms of acute heart failure. She was diagnosed with new-onset AF and rapid ventricular response. After successful rate control with a β-blocker and anticoagulation with heparin, she underwent successful cardioversion after a transesophageal echocardiogram demonstrating no thrombi or valvular heart disease with an ejection fraction of 70%. Her other medications include ramipril and hydrochlorothiazide. Based on her CHADS2 score of 2 (hypertension and heart failure) and CHA2DS2-VASC score of 3 (hypertension, age 65–75 years, and female sex) a decision is made to anticoagulate the …