Pros and Cons of Dabigatran and Warfarin
Warfarin, a vitamin K antagonist, has long been the recommended drug for stroke prevention in patients with atrial fibrillation. However, use of warfarin is associated with a number of shortcomings, Dr. Diener pointed out. “It is difficult to handle,” he said. “You have to keep your patients in a very narrow range of anticoagulation, which is measured by international normalized ratio [INR]. If people are below 2, they have an increased risk of ischemic stroke. And if they [have an INR of] about 3 to 4.5, they have an increased risk of hemorrhage, including cerebral hemorrhage. This makes this drug difficult, because it also has an interaction with other drugs and with food, so there is a continuous need of monitoring this.”
In contrast, dabigatran is taken in a fixed dose, twice daily, independent of body weight, sex, or food. “And you don’t need to monitor the coagulation system,” Dr. Diener emphasized.
Dabigatran is currently approved outside the US for primary prevention of deep vein thrombosis and pulmonary embolism among patients who have undergone elective hip or knee surgery. Once it becomes available in the US, the drug may not be ideal for all patients, according to Dr. Diener.
“This will be a cost-efficacy question,” he said. “If a patient is taking warfarin long term and has stable INR values, there is no need to change. If a patient has changing INR values all the time and 50% of the time is outside the therapeutic range—not due to poor compliance—this patient would be a clear candidate for dabigatran.
“I think the most important message for neurologists is in the 70% to 85% relative reduction in cerebral hemorrhage and intracranial bleeds with dabigatran compared to warfarin,” Dr. Diener commented. “We as neurologists and neurosurgeons are taking care of these patients, not the cardiologists.”
—Colby Stong