Pradaxa FDA Warning

The FDA’s 2010 approval of Pradaxa represented the first new anticoagulant to receive such approval in over fifty years.  Unfortunately, reports of life-threatening side effects began almost immediately, leading the FDA to expand and strengthen Pradaxa warnings several times in succeeding years.

To date, the agency has yet to issue a Pradaxa recall, despite escalating concerns about internal bleeding risks.

Pradaxa FDA warning

The FDA approved Pradaxa in October 2010 to prevent blood clots leading to stroke in patients with atrial fibrillation (irregular heartbeat).   At the time, the FDA listed the principal side effects of Pradaxa as dyspepsia (indigestion) and gastritis (inflammation of the lining of the stomach).  The agency noted that Pradaxa had no antidote, but advised physicians that “[i]n the event of hemorrhagic complications, initiate appropriate clinical support, discontinue treatment with Pradaxa, and investigate the source of bleeding.”

In addition, the FDA warned against temporary discontinuation of Pradaxa use, and instructed physicians to avoid using Pradaxa in patients taking rifampin (a tuberculosis drug) because of the risk of limiting the anticoagulant effect.

Just five months later, the FDA required Pradaxa’s manufacturer to include new warnings on the drug’s label.  The agency’s March 2011 communication added a warning against prescribing Pradaxa to patients being treated with anti-arrhythmia drug dronederone, because the anticoagulant effect became up to twice as high.

In November 2011, the agency again revised required warning language on Pradaxa’s label.  In this instance, the FDA noted that Pradaxa’s anticoagulant effect intensified in patients with renal impairment (reduced kidney function).  The agency instructed physicians to reduce Pradaxa dosage in patients with moderate renal impairment who also were being treated with certain anti-arrhythmia drugs, and to avoid Pradaxa use altogether in patients with severe renal impairment who were taking anti-arrhythmia medications.

January 2012 saw yet another strengthening of the warnings on Pradaxa’s label.  The FDA required the drugmaker to recommend that physicians assess kidney function before and during Pradaxa usage in order to prevent patients’ overexposure to the anticoagulant.  In addition, the FDA recommended that doctors discontinue Pradaxa in patients who develop acute renal failure.  The new label was required to state that “Pradaxa’s anticoagulant activity and half-life are increased in patients with renal impairment.”  Finally, the agency directed the new label to advise that patients “Call your healthcare provider right away if you fall or injure yourself, especially if you hit your head. Your healthcare provider may need to check you.”

In April 2012, the FDA required more Pradaxa warning information.  For the first time, the label disclosed that Pradaxa users suffered an increased risk of myocardial infarction (heart attack) compared to users of Warfarin, the anticoagulant that had been in use since the 1950s.

Health regulators ordered further Pradaxa warnings in November 2012.  After this date, the drug’s label questioned the use of Pradaxa in patients with artificial heart valves, noting that no studies had been conducted on Pradaxa’s effect on such patients.  And the label identified a new adverse reaction reported by patients using Pradaxa:  angioedema (swelling under the skin that can be fatal if experienced in the larynx).

One month later, the FDA required the Pradaxa label to warn against use of the drug in patients with mechanical prosthetic heart valves.  The study examining Pradaxa use among such patients was terminated early due to the number and severity of the side effects, which included stroke, heart attack, valve thrombosis, heart attack, and a disproportionate number of major internal bleeding events.

Black box warning for Pradaxa

In April 2013, the FDA required Pradaxa’s label to include a “black box warning,” the strongest caution available to the agency.

The new label included the following language:  “WARNING:  DISCONTINUING PRADAXA IN PATIENTS WITHOUT ADEQUATE CONTINUOUS ANTICOAGULATION INCREASES RISK OF STROKE.”

The label also added another adverse reaction reported by Pradaxa users to the FDA:  thrombocytopenia (abnormally low number of platelets in the blood).

December 2013 saw yet another new complication reported by Pradaxa users that the FDA required to be added to the drug’s label.  Esophageal ulcers had been reported to the agency as an adverse event, and the FDA required its inclusion on the label as a possible complication of Pradaxa use.

The FDA’s many required revisions to the Pradaxa label implies that the drug’s original labeling failed to provide adequate warning to patients and physicians about Pradaxa’s many serious and life-threatening complications.

Many of the Pradaxa lawsuits pending across the country, particularly in the multidistrict litigation in federal court in the Southern District of Illinois, have charged that Pradaxa’s manufacturer breached its obligation to disclose comprehensively the risks and benefits of Pradaxa use.  As that litigation goes forward, and the FDA continues to review data surrounding Pradaxa’s risks, additional allegations of inadequate warnings may well be revealed.

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