At Increased Risk Are Patients Who Are Older, Have Altered Renal Clearance, Or Undergoing Atrial Fibrillation (AF) Ablation
(Posted by Tom Lamb at DrugInjuryWatch.com)
We first reported about Pradaxa (dabigatran) back in October 2011 in this article "New Heart Drug Pradaxa May Be Sending "Early" Drug Safety Signals".
Our source back then and now, for this 2012 update, is the ISMP QuarterWatch publication, which monitors FDA MedWatch Reports for emerging drug safety issues.
From the ISMP QuarterWatch 2011 Quarter 1 edition, which was published January 12, 2012, we get this summary of what has been reported to the FDA as regards the "substantial bleeding risks" associated with Pradaxa:
[Pradaxa] accounted for 505 reported cases of severe bleeding resulting in death, disability, hospitalization or other serious outcome in the first quarter—more than any other drug we regularly monitor. The hemorrhage cases were occurring in the oldest patients with a median age of 80, and 25% of patients experiencing hemorrhage were 84 years or older, raising the question of whether the oldest patients are getting too high a dose.
In particular, gastrointestinal hemorrhages and hemorrhagic strokes were identified as some of these serious side effects in this elderly patients using Pradaxa.
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Returning to the January 2012 ISMP QuarterWatch report:
Declining or impaired kidney function—which also occurs in older patients—is a second and potentially related safety issue associated with possible overdose and bleeding. In pharmacologic studies of dabigatran, patients with mild kidney impairment had dabigatran blood levels that were 50% higher than patients with normal kidney function, and moderately impaired kidney function could result in blood levels that were three times higher.
We turn next to a February 8, 2012 article, "More bleeding, thromboembolic events with dabigatran in AF ablation", published online at theheart.org:
A feasibility study testing the potential periprocedural use of [Pradaxa] during radiofrequency ablation of atrial fibrillation (AF) has shown the new anticoagulant increases the risk of bleeding or thromboembolic complications compared with uninterrupted warfarin therapy....
"The lack of any recommended acute reversal agents for dabigatran, at present, makes the risk of excessive bleeding complications all the more important," write [Dr Dhanunjaya Lakkireddy] and colleagues in their report, published online February 1, 2012 in the Journal of the American College of Cardiology ["Feasibility and safety of dabigatran versus warfarin for periprocedural anticoagulation in patients undergoing radiofrequency ablation for atrial fibrillation"].
Of course, we will continue to watch for further developments regarding the safety of this relatively new anticoagulant drug Pradaxa, especially those involving the serious bleeding events that have been reported to the FDA.
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