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warfarin usage and memory loss

"The study doesn't suggest we need more blood thinning," Bunch says, "but that we need more effective blood thinning."

"It makes absolute sense," he says. However, he concedes, it can be difficult for patients with atrial fibrillation to stay in that optimal range. This is because warfarin can interact with other drugs. And certain foods and drink (greens, alcohol) can affect how well warfarin works.

The study found a strong link with the amount of time a patient’s INR was in a target range and the likelihood of developing dementia. While this can't prove cause and effect, the researchers did find a strong correlation. Those who had an INR in the target range (2 to 3) more than 75 percent of the time — were four times less likely to develop dementia than those in the target range only 26 to 50 percent of the time.

Warfarin Levels & Dementia: Second Opinion

Atrial fibrillation patients who maintain target blood levels of warfarin most of the time have lowest dementia risk, experts find.

He found an increased risk of dementia not just when blood levels were below the target. There was also a suggestion of increased risk when the blood level is too high, particularly in patients over 80 yrs old. If the blood level is too low, there is a danger of developing blood clots, which increase the risk of strokes, experts know. However, if blood levels are too high, there can be brain bleeds, which can also compromise the brain.

The new findings definitely suggest that keeping warfarin within the ideal range provides dementia protection as well as stroke protection, says Luigi Di Biase, MD, PhD, senior researcher at the Texas Cardiac Arrhythmia Institute, St. David's Medical Center, Austin. He reviewed the findings.

The study, published August 2014 in Heart Rhythm included 2,600 patients. Their average age was 74. None had dementia at the study start. But by the end of the five-year follow up, 109 patients had been told by a neurologist that they had dementia.

Patients taking warfarin are required to undergo regular blood tests to monitor the drug’s effectiveness. Avoiding monitoring can result in incorrect dosages and an increased risk for excessive, potentially life-threatening bleeding of the gastrointestinal tract and other regions of the body.

Warfarin (also known under the brand name Coumadin), a blood thinner that has been around for decades, can trigger a range of side effects. Some of the side effects include nausea, vomiting, diarrhea and abdominal pain. The most common side effect — bleeding — can be life-threatening. Rare side effects include stroke, gangrene and death.

Less Common Side Effects

Major and sometimes deadly bleeding usually occurs within the first month of a patient using warfarin, according to the drug’s label. Patients are more likely to experience this side effect if they have an elevated International Normalized Ratio (INR), a measure of how long it takes a person’s blood to clot.

The symptoms include a bluish or blackish discoloration of the skin along with pain and numbness in the region. The skin eventually breaks down into sores that have a foul-smelling discharge. Gangrene and necrosis can affect the skin and internal organs. It is a dangerous and potentially deadly condition that usually requires surgery, antibiotics and oxygen therapy. Severe cases can lead to amputation.

While an INR of 1.1 or less is normal in a healthy person, individuals using warfarin usually need to keep their INR in a therapeutic range of 2.0 to 3.0. Every single-point increase in a person’s INR doubles the bleeding risk. An INR over 4.0 can be a sign of thinning the blood too much, which increases a patient‘s risk for major bleeding.