Issues With Newer Oral Anticoagulants

Posted on: December 13, 2013

Issues With Newer Oral Anticoagulants

Dr. Robert Robles Treatment for a deep venous thrombosis (a blood clot – typically in the leg) and/or pulmonary embolus (a blood clot in the lungs) has followed a standard treatment regimen for many years. Originally, intravenous heparin – requiring hospitalization – followed by warfarin pills was the standard care. More recently, the use of low molecular weight heparins or fondaparinux (Arixtra) can be given as injections under the skin, followed by warfarin, has become a more convenient and equally effective treatment protocol. The recent approval of newer oral anticoagulants deserves some review and discussion. Dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis) are oral anticoagulants approved for the prevention of stroke in atrial fibrillation. Rivaroxaban (Xarelto) is also approved for the treatment of deep venous thrombosis and pulmonary embolus and for blood clot prevention following knee or hip joint replacement surgery. These oral drugs have made long-term anticoagulation much simpler. There is no need for routine monitoring and there are few interactions with food or other medications. However, each of these drugs has elimination through the kidney and safe dosing requires accurate assessment of the kidney function. Overall, the risk of bleeding associated with these new medications is equivalent to warfarin. A commonly asked question is how to manage bleeding for patients on one of the newer oral anticoagulants. There are no approved reversal agents for these medications. Vitamin K and fresh frozen plasma – used to reverse the effect of warfarin – are ineffective in reversing the blood thinner effect of the newer oral anticoagulants. Special kidney dialysis techniques may remove some dabigatran (Pradaxa), while rivaroxaban (Xarelto) and apixaban (Eliquis) cannot be removed effectively by standard kidney dialysis. Orally administered activated charcoal given within 2-6 hours of the last dose of apixaban (Eliquis) may help reduce further absorption of this drug and can also be considered for rivaroxaban (Xarelto). Standard coagulation studies such as aPTT and PT/INR are not helpful in monitoring the anticoagulation effect of these drugs. However, these tests can be used to determine whether or not the blood thinning drugs are still present. Non-approved therapies for acute bleeding have utilized activated prothrombin complex concentrates (APCC) and factor VIIa. These drugs need to be used very carefully as they can provoke excessive clotting. These medications do not provide full reversal of the anticoagulant effects of the new oral anticoagulants. In summary, the new anticoagulants provide equal benefit and no extra risk for individuals requiring blood thinners. However, like all new medications, they pose unique challenges to safe use. Robert Robles, MD is Board Certified in Medical Oncology and Hematology.  He practices with Diablo Valley Oncology/Hematology Medical Group, located at the California Cancer and Research Institute in Pleasant Hill and also sees patients in San Ramon.  Dr.Robles can be reached at 925-677-5041. Tags: ,