Warfarin is an anticoagulant or blood thinner, which reduces the formation of blood clots. Blood thinners prevent dangerous blood clots that can obstruct the blood flow to the vital organs. Patients taking warfarin require close monitoring and regular blood tests as well as dietary and lifestyle changes. In the last couple of years, Xarelto and Pradaxa were designed to avoid the negative aspects of warfarin.
Xarelto (rivaroxaban) is a new anticoagulant developed by Bayer and Johnson & Johnson’s New Jersey-based unit, Janssen Pharmaceuticals. The Food and Drug Administration (FDA) approved Xarelto for use in patients who have had knee or hip replacement surgery to reduce the risk of blood clots, reducing the risk of stroke in people with atrial fibrillation. The FDA approved the drug for general treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE).
One of the most severe side effects of Xarelto is uncontrolled bleeding. When bleeding occurs near a major organ, such as the brain, kidneys or lungs, blood flow to that organ is interrupted, causing it to lose some or all of its functionality. In addition, pools of blood may form within the body and can cause other severe health risks. Because Xarelto prevents clotting, the hemorrhaging will continue until the drug is flushed out of the system.
Pradaxa (dabigatran) was developed to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation, for the treatment of DVT and PE. However, growing complaints of risks and deaths tied to the new crop of drugs, such as Xarelto and Pradaxa, have made some top cardiologists hesitant to prescribe them. Some doctors are proposing a more rigorous monitoring regimen for when they are used.
Pradaxa is also associated with greater bleeding risks than warfarin among older adults with atrial fibrillation, according to a retrospective analysis in JAMA Internal Medicine. Using Medicare data on adults who were newly diagnosed with atrial fibrillation in 2010 – 2011, researchers compared outcomes in some 1,300 that filled prescriptions for Pradaxa and 8,100 that filled prescriptions for Warfarin. During a roughly 6 to 8 months’ follow-up, Pradaxa users had significantly higher bleeding risks than Warfarin users in terms of any bleeding (33% vs. 27%), gastrointestinal bleeding (17% vs. 10%) and major bleeding (9% vs. 6%). Intracranial hemorrhage occurred more often with Warfarin (0.6% vs. 1.8%). The risk for major bleeding with Pradaxa was particularly high for African-Americans and patients with chronic kidney disease.
Pradaxa and Xarelto, which do not require regular blood monitoring or frequent doctor follow-up, raises concerns about the risk of stroke, serious bleeding and blood clots if not taken properly, particularly in patients with poor kidney function.
Doctors stress that Xarelto and Pradaxa don’t have an antidote for uncontrollable bleeding, whereas warfarin does. Boehringer Ingelheim said it is working on an antidote for Pradaxa. Johnson & Johnson said it is not developing an antidote for Xarelto, but is monitoring efforts by other drugmakers to come up with one.