Farmacocinética y farmacodinamia de los nuevos anticoagulantes orales

Management of Anticoagulation in Patients With Prostate Cancer Receiving Enzalutamide

Enzalutamide, a novel, oral androgen receptor antagonist used for the treatment of metastatic, castration-resistant prostate cancer, has been shown to improve overall and progression-free survival, prolong time to initiation of chemotherapy, reduce skeletal-related events, and carry a favorable adverse effect profile. Metastatic prostate cancer is a disease of older men, a population with an increased incidence of medical comorbidities warranting anticoagulation. Prostate cancer itself, along with some of its therapies, is also prothrombotic. Enzalutamide interacts with several anticoagulants through various mechanisms, making their concurrent use clinically challenging. As such, complex decisions about anticoagulation in these patients are frequently encountered by treating physicians. In this review, we describe the potential interactions between enzalutamide and various anticoagulants, and suggest management paradigms based on the current body of knowledge for patients with atrial fibrillation, venous thromboembolism, and mechanical heart valves.

Old versus new oral anticoagulants: focus on pharmacology

Since the discovery of heparin nearly a century ago, there have been large gaps in the development of anticoagulants. The discovery of warfarin was the first step toward using oral anticoagulants, but warfarin use has been associated with its own challenges from the perspectives of the prescribing physician and the patient. Warfarin, along with other coumarins, has a narrow therapeutic index, requires frequent monitoring, exhibits interindividual response variations, and is associated with several adverse effects. Frequent drug and food interactions contribute to potential safety and efficacy compromise. The indications for use of oral anticoagulants have increased, as these drugs are used not only for thrombosis management but also for cardiovascular indications, producing more challenges for oral anticoagulant use. Factor Xa and thrombin targeting has provided a rational approach to develop new oral anticoagulants with improvements over warfarin. In this review, the pharmacology of warfarin and the pharmacology of the newly developed oral anti-Xa and antithrombin agents are discussed.

[Should dabigatran or vitamin K antagonists be used in prevention of stroke in patients with atrial fibrillation?]

Patients with atrial fibrillation (AF) at risk of stroke are not always anticoagulated with vitamin K antagonists (VKA) despite lack of contraindication. Dabigatran, an oral direct thrombin inhibitor, is a new option with proven safety and effectiveness in these patients. The advantages of dabigatran are its more predictable response, obviating coagulation monitoring and possible lower frequency of bleedings. Its drawbacks are cost, lack of antidote and long-term data, frequency of dyspepsia and the twice daily dosage.