Pradaxa approved by FDA to prevent stroke: Is Pradaxa safer and better than warfarin?

21 Oct 2010

On October 19th, 2010 the FDA approved the drug Pradaxa (dabigatran) for prevention of stroke and blood clots in people with abnormal heart rhythm (atrial fibrillation). As compared to warfarin, Pradaxa does not require laboratory monitoring. In one study, people who took Pradaxa had fewer strokes than those who took warfarin. However, Pradaxa is still capable of causing serious bleeding, as is experienced with warfarin, although Pradaxa is less likely to cause intracranial hemorrhage but more gastrointestinal bleeding. Common side-effects seen with Pradaxa are gastrointestinal symptoms which are occur in about 1/3 of users, which includes dyspepsia (generalized stomach discomfort), stomach pain, nausea, heartburn, and bloating. Pradaxa will be available in 75 and 150mg capsules. Pradaxa has been used in Europe and Canada since 2008.

Of interest is that the RE-LY Trial compared various dosing regimens of Pradaxa to warfarin and the 150mg twice daily regimen was superior to warfarin, but also caused the same amount or rate of bleeding as warfarin. The 110mg twice daily regimen showed less bleeding than warfarin but was equally effective yet not superior to warfarin. All-cause mortality was the same in each group, Pradaxa vs. warfarin, and there was a higher rate of heart attacks in the Pradxaxa group (0.74% vs. 0.53%). So is this drug really superior and more advantageous to warfarin? One must also consider Pradaxa costs about ten times more than warfarin, even when we include the cost of routine monitoring as required with warfarin. We’ll need to dig further to see if there are data for the use of this drug in the older adult population such as the old-old adult over 80 (Note: In those >75y/o there was a higher rate of bleeding as compared to warfarin). We will also need more information on drug interactions, a big concern and area of risk with warfarin. For now, if you are well managed on warfarin with stable INRs and no evidence of bleeding, there is no reason to change to Pradaxa. The FDA link is below with the official press release.

http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm230241.htm

14 Comments

sharon beccacio December 3, 2010 at 11:27 pm

Why doesn't this drug require monitoring of PT or INR? Is it not necessary or are the tests tht woudl monitor it not available in the physician's office yet? Also, what does this drug do to the liver, there is no mention of the actual mechanism that is altered and how it is altered by this drug?
Alan Lukazewski December 4, 2010 at 11:03 am

I'll try my best to give you some logical explanation, but I encourage you to keep in mind I am not an anticoagulation expert. From the literature I can extract that dabigatran does not need monitoring simply because in the Phase III clinical trials they showed that it was not necessary. This is so is because it doesn't have the narrow therapeutic index that warafrin has, where frequent monitoring is needed in order to keep the therapeutic effects in the narrow range. However, in some situations monitoring dabigatran may prove beneficial. There were two situations in which examples were given, those being in low body weight individuals (<50kg) and those with reduced kidney function (CrCl <50ml/min), suggesting the drug has enhanced effects in these subjects. It was commented in the NEJM that monitoring clotting time might prove useful in this unique subset of patients when determining if they could go into surgery, for example, and would need to be off the drug a longer period of time before having surgery. Dabigatran is a direct inhibitor of thrombin, which acts to form strong fibrin clots, the final step of the coagulation process. Regarding its effects on the liver, dabigatran is not a substrate, inducer nor inhibitor of liver enzymes, so it does not appear to cause any liver damage. From the product labeling, use in those with moderate liver function impairment resulted in no change in effects of the drug or alteration of risk for bleeding.
Kenneth C. Pewters January 24, 2011 at 11:02 am

I have been on pradaxa (150mg) for only 34 days but 7 days ago my kidney's began to ache & the Dr. prescribed ciprofloxacin -150mg (Cipro) & within 2 days my joints ached & my knees hurt so bad I could hardly walk without a cane. I also am having trouble sleeping nights.
Kenneth C Peters January 24, 2011 at 11:06 am

Does or can pradaxa cause kidney damage. I have only been on it for 34 days and my kidneys started to ache 7 to 10 days ago
Alan Lukazewski January 25, 2011 at 7:12 am

Pradaxa is not known to cause kidney damage and if you have such symptoms you should talk with your physician ASAP to find out what's going on. The only correlation between reduced kidney function and Pradaxa that I know of so far, is that the drug can accumulate in the body in those with reduced kidney function thereby increasing the risk for side-effects, such as bleeding.
Cody Jackson February 9, 2011 at 1:07 pm

Pradaxa was probably not the cause of either problem. As Alan stated (thought I myself and not that familiar with) Pradaxa is not noted to have kidney damage and quite possibly your symptoms were due to a kidney infection. This is why you were prescribed Cipro. However, Cipro and antibiotics in that same class (known as fluoroquinolones) have been proven themselves to cause joint pain and damage. You should have contaced your doctor immediately to get changed to a different antibiotic and assess any joint damage that may have occured.
Nevin February 22, 2011 at 4:16 pm

My guess is that Pradaxa is not prone to the same fluctuations in INR blood readings as Warfarin as long as you take it regularly as prescribed. However, let's face it, Pradaxa is so new, terribly expensive and only slightly more effective. It needs a few years. Another option is a stent.
Alan Lukazewski February 24, 2011 at 9:53 pm

Pradaxa mainly affects other clotting measurements such as activate partial thromboplastin time (PTT), ecarin clotting time (ECT) and thrombin time (TT). ECT is the best marker of Pradaxa activity but not always available. PTT can function as a marker of the drug's anticoagulant activity. You are correct in saying that Pradaxa will usually result in stable anticoagulant activity IF TAKEN twice daily, every day. Non-compliance or non-adherence could be an issue since the drug quickly loses effectiveness.
Susan Patti April 27, 2011 at 2:35 pm

My mother-in-law was just prescribed pradaxa. She also has magular degeneration in both eyes and periodically receives injections to minimize the bleeding in her eyes. Is there any data relating to this type of bleeding and taking pradaxa?
zelma messer May 8, 2011 at 10:43 pm

is it true that once you start taking pradaxa that you can't go off of it because you would have an increased risk of stroke or heart attack and if you did go off of it you would have to go on commadin.When do you think they will come out with a less expensive generic brand.
Jan August 8, 2011 at 5:15 pm

My mother age 84, was recently prescribed Pradaxa by a cardiologist. According to echo cardiograms, ekg, stress test, etc. thorough diagnostic testings resulted she had afib. Blood pressure was controlled, mild alzheimers no other medical problems. Took Pradaxa along with 81 mg of aspirin for nearly one month and unfortunately, passed away due to an intracranial hemorrhage. Began with excrutiating headache, and seizures, suffered severed damage to occipital lobe, temporal lobe, and perietal lobe. Neuro surgeons did not feel they could perform surgery due to the extent of damage the brain suffered. Doctors concluded that she was not a candidate for this lethal drug due to her age, low weight (97-1001lbs) etc. Please review all new medications prior to adminsitrating a new drug to your loved ones, especially the old-old patients over 80 . This drug is brand new just approved last October 2010 by FDA and patients should have their INR/PPT checked before and after treatment. It is honestly unpredictable to determine the coagulation of the blood without further testing.
Alan Lukazewski August 9, 2011 at 7:54 am

Jan Thank you for posting your comment. Sharing this information, although unfortunate news, is valuable for all to hear. I do not wish to extend your grief yet there is the opportunity to report this adverse drug event to FDA through the MedWatch program, where reported ADEs can then be followed up by FDA which can lead to labeling changes or other actions which can help prevent serious ADEs from occurring.
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Emma Jane Noll October 31, 2012 at 4:14 am

My mother, age 89 was prescribed Pradaxa as a precaution for stroke and heart attack. She had Atrial Fibrillation. She was a vibrant 89 year old and after taking this drug began not feeling well. Questioning her physician she was told the benefits outweighed the risk. Two months after beginning Pradaxa she experienced sharp stomach pains, constipation and a distended stomach. Her blood pressure dropped to very low levels and she had a weak pulse. She was so weak she could barely walk. She coughed up dark liquid (now described as looking like coffee grounds) which I have now learned was dried blood. A visit to her doctor resulted in him telling her to stop all meds until her blood pressure got to normal levels. It never did. She was rushed to the hospital yesterday, approximately 3 months after starting Pradaxa. The paramedics transporting her noted immediately her distended stomach and said she had internal bleeding. Unfortunately she started uncontrollable vomiting of blood and bile on her way to the hospital and the paramedics were unable to save her. We lost a vibrant mother, grandmother and great grandmother due to this drug and the failure of her physician to, first of all listen to her complaints when she had adverse symptoms.to the drug and secondly fail to realize on a visit to him the day before her death that she was bleeding internally. PLEASE intervene on behalf of the elderly, when they are given drugs with the track record this drug apparently has.

Pradaxa approved by FDA to prevent stroke: Is Pradaxa safer and better than warfarin?

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