Archive for the ‘Pradaxa’ Category

Follow-up Blog: Important questions and answers on Pradaxa

Monday, January 10th, 2011

Some months ago, we published a blog to announce what we thought was important medical news about a new product called Pradaxa. That blog, entitled A New Blood Thinning Drug is Approved – Pradaxa – better than Coumadin?, was widely viewed by many readers since October, 2010. Following our posting, a number of those readers have sent us questions about this new drug. To better serve our readers, we have invited Dr. Steven M. Davis to be our guest blogger on Pradaxa, and to answer some of these important questions.

Dr. Davis is the Associate Professor of Pharmacy at the Campbell University College of Pharmacy and Health Sciences in Buies Creek, NC. He is also the Clinical Coordinator for Pharmacy Services at Wake Forest University Baptist Medical Center in Winston Salem, NC. Dr. Davis has a PharmD with a specialty certification in geriatric pharmacology.

Below are the most frequently asked reader questions:

  1. How does Pradaxa differ chemically to Coumadin (Warfarin)?
  2. Do things with high Vitamin K (like spinach, lettuces, and broccoli) interfere with Pradaxa?
  3. If one were to start Pradaxa, how long would it take the blood to thin? If one were already taking Coumadin (Warfarin), what is the recommended method of switching to Pradaxa?
  4. How long would it take to reverse the effects of Pradaxa? I have been told Coumadin (Warfarin) stays in the body and before any surgery a patient has to wait 5 days.
  5. Why doesn’t the blood coagulation need monitoring if Pradaxa thins out the blood? Why wouldn’t the blood protime (PT) need monitoring with Pradaxa?
  6. How would someone adjust Pradaxa to keep the protime (PT) at a desired level?
  7. Are there any restrictions to other medications such as Aspirin?

Dr. Davis’ responses are listed below:

Question 1: Pradaxa (Darbigatran) is a direct thrombin inhibitor.  Thrombin is one of many clotting factors in the body necessary for coagulating blood.  Coumadin (Warfarin) works by a completely different mechanism. Coumadin/Wafarin prevents the activation of 4 clotting factors that depend on Vitamin K .

Question 2: Since Pradaxa works by directly inhibiting the clotting factor thrombin, the amount of vitamin K in the diet does not matter.

Question 3: When switching from Coumadin to Pradaxa, a physician will usually wait for a patient’s INR to drop below 2 before starting Pradaxa.  In most patients taking Pradaxa, blood will be appropriately thinned 2 to 3 days after starting the medication.

Question 4: Pradaxa is still a blood thinner and care must be used before surgery.  Pradaxa has a shorter life in the body (that is why it is dosed twice daily) and it is cleared from the body quicker than Coumadin (Warfarin).  It is recommended that a patient discontinue Pradaxa 1-2 days before surgery if they have normal kidney function and 3-5 days if they have impaired kidney function.  Of course you would NEVER stop this medication without consulting your physician first.

Question 5: Prothrombin time (PT) and INR measure the ability of Coumadin (Warfarin) to prevent the activation of the Vitamin K dependant clotting factors.  Again, since Pradaxa does not affect these factors, the prothrombin time does not change and, therefore, does not need to be monitored.

Question 6: The biggest advantage to Pradaxa is that there are fewer drug interactions, less food/drug interactions (Vit K containing foods), and thus no need to monitor prothrombin time or INR.

Question 7: Combining Pradaxa with aspirin will increase a patient’s risk of bleeding.  Both medications are used together frequently but ONLY under the direction of a physician.

Dr. Davis offers the following advice to patients considering taking or taking the drug Pradaxa.

This is a new medication and as with all new medications, it has not been used in a large population of patients yet.  New side effects and drug interactions may be discovered as this drug is used more frequently.  The Food and Drug Administration (FDA) monitors these reports and will issue statements as necessary.

From Brian Nash: I want to take this opportunity to thank Dr. Steven Davis for providing us with this information for our readers.

To our readers: Please keep in mind that we, at Nash & Associates, are not physicians. While Dr. Davis was so kind to provide the information he did regarding Pradaxa, this is not the usual approach we would take to our blog postings. From time to time we try to make you aware of important and/or interesting medical news. However, if you have questions about Pradaxa, we strongly urge you to speak with your personal physician.

UPDATE: Interesting piece by Dr. Wes on Pradaxa just posted today. Thought you may want to read. The comments have been coming in fast and furious on this new “wonder drug.”  Here’s the post by Dr. Wes – Pradaxa, Your Days are Numbered

A New Blood Thinning Drug is Approved – Pradaxa – better than Coumadin?

Friday, October 22nd, 2010

This week’s press release by the US division of the German based Boehringer Ingelheim pharmaceutical company is certainly a breakthrough for patients. The company announced the FDA approval of their drug Pradaxa (dabigatran etexilate). This is the first new oral anticoagulation drug approved in the US in more than 50 years.The drug was approved for stroke and systemic embolism prevention in people who have atrial fibrillation not caused by a failing/defective heart valve.

The press release touts impressive results. National studies have shown when Pradaxa 150mg was taken twice daily, there was a 35% reduction in stroke and embolism when compared with the traditional drug known to most as Coumadin (Warfarin). In addition, at the same dosing level both types of stroke (embolic/clot and hemorrhagic/bleeding) were greatly reduced when compared to Coumadin. More good news for patients taking the drug…

  • Very few drug interactions,
  • No more dietary restrictions, and
  • No more routine blood testing and dosing changes as required when taking Coumadin.

WHAT IS ATRIAL FIBRILLATION AND WHY DO YOU NEED TO TAKE BLOOD THINNING DRUGS?

Atrial fibrillation is a heart rhythm disorder caused by a malfunctioning electrical conduction system within the heart – see video.  It is usually identified by an irregular rapid heart rate that begins in the upper heart.The smaller 2 upper heart chambers, known as the atria, begin to contract quickly and in an irregular fashion. As electrical signals leave the atria and enter the 2 lower heart chambers known as the ventricles, they too begin to contract quickly and in an irregular fashion.  This irregular and rapid heart rate is unable to pump the blood through the heart and out to the body in a strong, efficient manner. Thus blood can pool in the heart and the lower extremities allowing clots to form. These clots dislodge and travel to the heart, lungs, and brain leading to a stroke. Therefore it is important to prevent the clots from forming by correcting the abnormal heart rhythm,  and by lowering the blood’s ability to form dangerous clots.

The press release noted an estimated 2.3 million Americans have atrial fibrillation and the number is expected to increase to 5.6 million by 2050. A large US-based managed care organization used their data to show 95% of all persons with atrial fibrillation have no heart valve problems. Atrial fibrillation increased the risk of stroke 5 times, and is an underlying condition in 15% of all US strokes. Atrial fibrillation related strokes are twice as likely to be fatal or severely disabling when compared to strokes from other causes.

MedicineNet.com today reported recent studies by the New England Journal of Medicine and the American Heart Association found Pradaxa was also more effective in preventing clots in patients experiencing acute coronary syndrome. Sweden reports the drug can be safely used in conjunction with Plavix and Aspirin drug therapies.

WHAT ARE THE DOWNSIDES?

With the good news, comes the drug’s downside. The company is forthcoming in reporting Pradaxa when administered in 150mg doses results in a higher rate of gastrointestinal bleeding related complications when compared to Coumadin. This dose was reported to also cause an increase in adverse GI reactions such as dyspepsia, abdominal and gastric pain, GERD, esophagitis, gastritis, and ulcer. Importantly, in patients older than 75 years of age, the risk of bleeding complications may be greater than Coumadin. Also noteworthy is the finding that the risk of myocardial infarction was greater in studies with patients taking the 150mg dose than those taking Coumadin.

The company warns patients taking other blood thinners, non-steroidal anti-inflammatory medicines, St. John’s Wort, and any drug that can cause abnormal bleeding reactions need to be avoided. Over the counter medications are included in this warning. The company’s public package leaflet notes the drug will interact with Amiodarone and Verapamil and Pradaxa dosing will need to be reduced. The drug may also affect the liver but not more then Coumadin. It is contraindicated in patients who are in kidney failure, liver failure, and pregnancy. Some report a Quinidine interaction.

The FDA has approved dosing in capsule forms of 75mg and 150mg twice a day. Those persons taking larger doses of 150mg need to be fully informed of the above possible complications before switching from Coumadin to an easier life with Pradaxa.

EASIER TO LIVE WITH, BUT WHAT WILL IT COST?

It will take 3 to 6 months before distribution begins and pricing is not known. As with any new drug introduced in the US, speculation is the cost will be just short of prohibitive. Canada Pharmacies online sell Pradaxa 60 capsules both 75mg and 150mg doses at approximately $350.00 each. Generic Coumadin 100 pills at variable doses sell for approximately $34.00 to $50.00. The high drug price for US patients may offset the life style improvements for many who pay out of pocket for drugs. It is not known if prescription drug plans will approve partial or full payment for the drug.

It is generally reported that Coumadin is not a popular drug. Consumers and physicians alike resound with the same low opinion of the drug.  It is a difficult drug for physicians to manage, and it has a great impact on quality of life for patients. If Pradaxa continues to show its improved lifestyle value with no hidden serious side effects, patients will be the winners. Hopefully over time competitors will surface and prices will be driven into an affordable range for the growing US atrial fibrillation patient population.

UPDATE: Interesting piece by Dr. Wes on Pradaxa just posted today. Thought you may want to read. The comments have been coming in fast and furious on this new “wonder drug.”  Here’s the post by Dr. Wes – Pradaxa, Your Days are Numbered

Related Post:

Follow-Up Blog: Important Questions and Answers on Pradaxa