Overview: Pradaxa’s safety issues are once again being emphasized, as the preliminary results of a study show that it may be associated with more adverse events than warfarin. While the relatively recent blood thinner was thought to be a more convenient option, additional research indicates that the risks need to be further investigated.
- Study shows 0.88% of warfarin-linked events leading to drug discontinuation compared to 11.5% Pradaxa-linked events, with one case resulting in fatality
- Pradaxa events include a long list of different types of bleeds
- Contrary to popular practice, Pradaxa does require monitoring
- Because Pradaxa leaves the body faster than warfarin, patients have to be more diligent in complying with their prescriptions
- Unlike warfarin, there is no reversal agent for bleeding in Pradaxa patients.
Product: Pradaxa (dabigatran)
Manufacturer: Boehringer Ingelheim Pharmaceuticals
Side Effects & Complications
- Cerebral hemorrhaging
- Gastrointestinal (GI) hemorrhaging
- All types of bleeds including the intraspinal, intraocular, intraarticular (joints), retroperitoneal or pericardial areas
The preliminary study results were presented at the Thrombosis & Hemostasis Summit of North America 2012 by Dr. Mark Wurster. The real-world study looked at the number of adverse events resulting in drug withdrawals over a six-month period for 113 patients who switched from warfarin to Pradaxa. Wurster only noted one warfarin-linked event (0.88%) requiring discontinuation due to a high INR (a test used to monitor the effectiveness of anticoagulants). With Pradaxa, there were 13 adverse events (11.5%) that led to withdrawal, including:
- One treatment-related death (GI bleed)
- Two GI bleeds
- One rectus sheath hemorrhage
- One deep venous thrombosis
- One atrial thrombus
- One transient ischemic attack
- One skin rash
- Four GI symptoms
- One intracranial hemorrhage
Pradaxa has often been hailed as a better alternative to warfarin because it doesn’t require frequent blood tests, but Wurster says that notion may actually account for some of his findings. “The problem with dabigatran is that it has been presented as a ‘fire-and-forget’ medicine. That is, the doctor can write a prescription and not think about it again. But anticoagulation is not like that. Just because patients on dabigatran don’t need to have regular INR measurements doesn’t mean they don’t need monitoring.” he said to Heartwire. Wurster recommends that patients taking Pradaxa be assessed every three months. He also notes that Pradaxa has a shorter half life, meaning it is less forgiving for those who occasionally miss a dose. Wurster told Heartwire, “I’ve seen two cases where patients have missed two or three doses and had a major clot within two days.”
Pradaxa has another major downside; because it is part of a class of drugs known as direct thrombin inhibitors, there is no antidote to stop the bleeding, aside from dialysis. Warfarin on the other hand, is a vitamin K antagonist, and bleeding in these patients can be reversed with vitamin K or fresh frozen plasma. If this preliminary data is truly indicative of an overall trend, then Pradaxa patients may be at even greater risk than previously thought.