Blood thinning, anticoagulant warfarin (Coumadin) carries risk of a brain hemorrhage. This is a risk of its use that is not always being considered by the prescribing doctor.
The rate of bleeding in the brain associated with use of the anticoagulant drug warfarin quintupled during the 1990s, University of Cincinnati researchers reported Monday.
Moreover, in people over 80, the rate of brain hemorrhages associated with warfarin, best known as Coumadin and used to thin the blood and prevent strokes, increased more than tenfold, according to the study, published in the Jan. 9 issue of Neurology.
“Warfarin use increased during the 1990s, because it was proven to be effective in preventing ischemic strokes among people who have an abnormal heart rhythm called atrial fibrillation,” said the study’s lead author, Dr. Matthew L. Flaherty, a neurologist.
The drug is commonly prescribed to prevent blood clotting, which can lead to ischemic stroke, the most common type of stroke. However, warfarin is associated with another type of stroke, called an intracerebral brain hemorrhage, which is a ruptured blood vessel resulting in bleeding in the brain, Flaherty explained.
One expert thinks that doctors need to evaluate a patient’s risk of stroke versus their risk of bleeding before prescribing warfarin.
“This study demonstrates that we need to be careful when we use these therapies,” said Dr. Michael B. Rothberg, an associate professor of medicine at Tufts University School of Medicine.
Not all patients with atrial fibrillation will benefit from warfarin, Rothberg added. “Not all patients with atrial fibrillation should be getting warfarin,” he said. “Patients at the highest risk for stroke will benefit the most, and patients at the highest risk for bleeding will benefit the least,” he said.
Rothberg noted that although warfarin is standard treatment for atrial fibrillation, not everyone with atrial fibrillation is at the same risk of stroke. “I don’t think that most doctors prescribing warfarin are assessing their patient’s risk of stroke and risk of bleeding, but they should be,” he said.
In addition, Rothberg also believes that better INR monitoring could help reduce the problem of bleeding.