Sunday, May 1, 2011

Pradaxa...A Dangerous Drug?

Lately, I have made reference to a recent new drug that was approved by the FDA called Pradaxa (trade name).  This drug is licensed as a blood thinner to be used specifically in patients who may develop blood clots as a result of an abnormal and irregular heart rhythm known as atrial fibrillation.  The more commonly used drug is Coumadin or warfarin.  The problems with using the latter is that frequent blood tests need to be conducted to monitor the level of "blood thinning" and many patients need frequent adjustments in their dosing.  A common problem is that people forget to have the blood test performed or inappropriately take the wrong doses because many adjustments need to be made.  If patients' levels are too high, it increases their bleeding problems if they were to develop a bloody nose, GI bleed, or head injury as the result of a fall.

When people are taking Coumadin and their levels are too high and they suffer an injury or complication, the level of "blood thinning" can be reduced if they are actively bleeding by administering Vitamin K and blood product, the most common known as fresh frozen plasma.  These will "reverse" the level of blood thinning and return levels back to normal depending on how much "antidote" is given.  This is especially important if one falls and hits his or her head and develops bleeding ot hemorrhaging in their brain which often is fatal.  Of course if the effects are reversed, the patient is then put at risk for developing clots from the atrial fibrillation which can cause a stroke.  Obviously, the benefits outweigh the risks if someone is actively bleeding.  This is especially true with life threatening bleeding from accidents, nose bleeds, or GI bleeding (ulcer or rectal which tend to increase as one gets older).  Blood tests can also be performed to ascertain the level of "blood thinning."

With the use of Pradaxa, the level of "blood thinning" cannot be accurately determined with a blood test.  Likewise, there is no immediate antidote.  So if a patient is taking the oral medication and develops an injury or bleeding problem, there is little that can be done other than replacing the blood with additional blood transfusions.  Most people who are taking Pradaxa are older and have co-morbid underling medical conditions which inherently place them at higher risks for bleeding complications.

Physicians in Emergency Departments are often the first ones to encounter such complications. I have personally cared for patients who have become hypotensive (low blood  pressure) secondary to hemorrhage from nose bleeds and GI bleeds (rectally) that have nearly exsanguinated (bleed to death) because I could not give them blood fast enough.  If these patents were on Coumadin, I would have at least been able to try to successfully counteract the effects with antidotes.  With Pradaxa, you have to basically wait for the drug to be excreted out of the body.  There have been very limited studies to suggest that renal dialysis may help.

I suspect that as more patients are placed on Pradaxa, we will eventually see more serous side effects of the drug...time will tell, but I suspect at the cost of additional lives.