Bleeding side effects in patients treated with dabigatran (Pradaxa) have led a group of New Zealand hematologists to sound the alarm and call for better prescriber education.
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The hematologists wrote of their concerns in a letter published in the March 1 issue of the New England Journal of Medicine. In a two-month review, they identified 78 bleeding episodes, including 12 major bleeds, one of which might have contributed to a patient's death,
Many of the bleeding incidents involved older patients and patients with reduced kidney function. Importantly prescriber error occurred in about 25% of the complications, revealing a lack of awareness of the potential risks associated with the drug.
The researchers reported that,"bleeding is an expected complication of dabigatran, especially in the elderly, a risk that is not completely mitigated by a dose reduction: 22 of our patients had a bleeding episode while receiving a reduced dose."
In reviewing the clinical characteristics of their 44 patients, the authors noted that two-thirds were older than 80, a majority had moderate or severe renal impairment, and half had low body weight (<60 kg).
The patients differed substantially from those in the pivotal trial of dabigatran, whose study population had a median age of 71, median weight of 83 kg, and creatinine clearance that averaged 68 mL/min.
The authors noted that "our audit illustrates the difficulty in extrapolating trial data into clinical practice and emphasizes the need for post-marketing surveillance and adverse-event reporting to detect groups whose risk factors may not be apparent in a clinical-trial setting."
