The blood thinner Pradaxa was created by the pharmaceutical company Boehringer Ingelheim and is within a class of medications known as direct thrombin inhibitors. Direct thrombin inhibitors act as anticoagulants by directly preventing the action of the enzyme thrombin.

The U.S. Food and Drug Administration (FDA) approved the blood thinner Pradaxa on Oct. 19, 2010. It is used to prevent strokes, deep vein thrombosis and pulmonary embolism in people with non-valvular atrial fibrillation.

In people who have taken the anticoagulant to prevent strokes, it can only be taken by those with atrial fibrillation not caused by a heart valve issue.

Studies of blood thinner Pradaxa have concluded that it appears to be as effective as the drug warfarin in preventing embolic events and non-hemorrhagic strokes with those that suffer from atrial fibrillation but not in those that have a heart valve issue.

One common reported side effect is gastrointestinal upset. Researchers believe this side effect may have something to do with the capsules that contain tartaric acid. Tartaric acid is required for sufficient absorption of the drug, but it makes the interior of the stomach more acidic.

That increased acidity has been correlated to dyspepsia, which is pain felt in the upper middle part of the stomach. It has also been thought to increase the probability and risk for gastrointestinal bleeding.

Also, patients who have a mechanical prosthetic heart valve are not to use the blood thinner Pradaxa, as it increases the risk of thromboembolic events to occur. Such events can include myocardial infection, stroke and valve thrombosis.

One difference with blood thinner Pradaxa is that it does not have to be monitored with repeated blood tests, and it offers similar results in terms of its effectiveness.

But on the other hand, Pradaxa has been linked with reports of bleeding so excessive as to put the patient’s life at risk. In fact, the FDA reported that when comparing Pradaxa to warfarin in a study that included approximately 134,000 Medicare patients, it found that gastrointestinal bleeding was more common in Pradaxa patients than in those taking warfarin.

For years after Pradaxa was introduced, it had no available antidote. Unlike warfarin, which can be controlled by administering vitamin K, there was no other medication that could reverse the anticoagulant effect of Pradaxa in cases of excessive bleeding or where the patient suddenly needed emergency surgery.

An antidote, Praxbind (idarucizumab), was introduced in October 2015. But that antidote came too late for many Pradaxa patients who suffered from dangerous bleeding injuries before then.

Pradaxa bleeding events have been so widespread that they have led to a massive wave of products liability litigation. Plaintiffs in these Pradaxa lawsuits believe they were not adequately informed of the risks associated with this medication before they decided to take it. Many allege they could have avoided life-threatening Pradaxa bleeding had the drug’s manufacturer given them a more effective warning.