Novel anticoagulants like Pradaxa are promoted as having certain advantages over the older drug warfarin.

But like all anticoagulants, Pradaxa still creates a risk of internal bleeding like brain bleeds or gastrointestinal bleeding.

Pradaxa is a relatively new anticoagulant that has been available in the U.S. since first gaining FDA approval in October 2010.

Like many other anticoagulants, it’s frequently used to prevent the risk of stroke in persons with atrial fibrillation.

It’s also used to treat other blood-clot related injuries like pulmonary embolism and deep vein thrombosis.

According to the FDA, from the time Pradaxa entered the market in 2010 through December 2013, it has been prescribed 6.2 million times to 934,000 patients through outpatient pharmacies in the U.S.

Gastrointestinal Bleeding

In May 2014, the FDA released a Drug Safety Communication specifically addressing the risk of gastrointestinal bleeding associated with Pradaxa. The agency reported that in a study of over 134,000 Medicare patients age 65 and older, Pradaxa was associated with an increased risk of major gastrointestinal bleeding.

Symptoms of Pradaxa gastrointestinal bleeding may not be visible if the bleeding is very mild. In that case, testing a stool specimen can confirm if there is any bleeding going on.

Blood may be visible in vomit, and that’s usually a sign that the bleeding is coming from the upper GI tract – usually from the stomach or upper end of the small intestine.

Blood in vomit may take on the appearance of coffee grounds if the bleeding is slow. Faster bleeding may produce blood that retains its bright red appearance.

Gastrointestinal bleeding may also manifest as a black, tarry-looking stool known technically as melena. Melena may be an indicator that the bleeding is coming from the esophagus, stomach or small intestine. It may continue for several days after the bleeding has actually stopped.

As with darker-looking blood in vomit, the black color is a sign the blood has spent some time being exposed to stomach acids, enzymes, and bacteria in the large intestine.

Bright red blood in the stool may be an indication that the bleeding is coming from the large intestine.

Brain Bleeds

In the same study of Medicare patients cited by the FDA, Pradaxa was associated with a risk of intracranial hemorrhage. Anticoagulants in general create an increased risk of brain bleeds.

One of the more dangerous types of brain bleeds is a hemorrhagic stroke. This injury occurs when a blood vessel inside the brain leaks or ruptures.

The resulting brain bleed can simultaneously put pressure on the brain and deprive it of oxygen. Without oxygen, brain cells quickly begin to die.

A Pradaxa brain bleed can lead to impairment of whatever body function is related to the affected part of the brain.

The patient could suffer from impaired speech, difficulty swallowing, numbness or weakness, paralysis of some part of the body, or cognitive or emotional disorders.

New Pradaxa Antidote

Some of the controversy around Pradaxa and other new anticoagulants centers on the fact that they were approved for use before any antidote had been developed that could reverse their anticoagulant effect in cases of internal bleeding.

Pharmaceutical companies have since been working on antidotes for the new drugs. Praxbind, an antidote specific to Pradaxa, received FDA approval in October 2015.

However, patients who took Pradaxa in the years before the new antidote was available simply had to bear the risk of internal bleeding that could be difficult or impossible to control.