Blood Thinner Side Effects May Increase Risk of Dementia: Study

The findings of new research suggest that side effects of some blood thinners may increase a patient’s risk of developing dementia later in life. 

Researchers from Intermountain Heart Institute in Utah presented a study last Sunday at the American Heart Association’s annual conference in Chicago, which found that high levels of blood thinners, such as Coumadin (warfarin) and Plavix, may cause small amounts of bleeding in the brain.

Over time, individuals may face a significantly increased risk of dementia from these tiny brain hemorhages. The findings have not yet been published for peer review.

The study warns that the high variability of levels of warfarin and similar blood thinners over time can result in over-clotting and under-clotting causing the brain bleeds. Researchers looked at data on about 1,000 patients over 10 years who had no history of strokes or dementia.

According to the findings, patients who had bleeding problems while on the drugs that resulted in slow clotting 25% of the time or more had twice the risk of developing dementia when compared to those who had normal blood clotting 90% of the time while on the drugs.

Researchers determined that patients for whom warfarin is harder to regulate may face a greater risk. The researchers suggested that those patients may fare better and have less risk of dementia if given newer blood thinners, such as Xarelto, Pradaxa and Eliquis. However, those new generation anticoagulants have been linked to risks of their own in other studies.

New Blood Thinner Health Concerns

The anticoagulant warfarin, which is sold under the brand name Coumadin, has been the go-to blood thinner for prevention of stroke among individuals with atrial fibrillation for decades.

In recent years, factor xa inhibitors like Pradaxa, Xarelto and Eliquis have been introduced by drug makers attempting to capture the lucrative anticoagulant market. However, serious concerns have emerged about the safety of the drugs, as many users have experienced uncontrollable bleeding while using the newer medications introduced in recent years.

While all anticoagulants carry a risk of bleeds, doctors are able to quickly reverse the blood thinning effects of warfarin with a dose of vitamin K-based prothormbin complex concentrates (PCCs) and fresh frozen plasma (FFP), which acts as an antidote to reverse the medication if bleeding problems develop. However, no such reversal agent is available for Xarelto and other members of this new class, leading to a number of reports involving serious injury or death associated with uncontrollable bleeding.

Pradaxa was the first member of this new generation of drugs to be approved by the FDA in late 2010. However, shortly after it was introduced by the drug maker Boehringer Ingelheim, it quickly earned the dubious distinction as one of the most commonly cited medications in adverse event reports submitted to the FDA, often involving problems with uncontrollable hemorrhages and death.

Boehringer Ingelheim subsequently faced more than 4,000 Pradaxa lawsuits filed on behalf of individuals who alleged that the drug makers failed to adequately warn about the lack of a reversal agent. Earlier this year, the drug maker agreed to pay $650 million in Pradaxa settlements to resolve the litigation, averaging about $150,000 per case.

Amid concerns about the safety of Pradaxa, the second member of this class, Xarelto, increased in popularity. However, reports of bleeding complications with Xarelto have also begun to emerge, leading to a number of similar Xarelto lawsuits being filed against Bayer Healthcare and Johnson & Johnson’s Janssen subsidiary.

Many of the complaints allege that the drug makers should issue a Xarelto recall until a reversal agent can be developed, arguing that the bleeding risks outweigh any benefits provided over warfarin.

Lawsuits also allege that the manufacturers negligently failed to recommend blood monitoring on Xarelto, which may have allowed doctors to identify patients at greater risk of bleeds.