This page will provide you with a comprehensive overview of the blood thinner Pradaxa. Specifically, it will discuss why Pradaxa dosing, mechanism of action, efficacy and side effects are important to consider when using it as a treatment option. We sincerely hope that our website helps to further your understanding of the importance of Pradaxa dosing and control. If you have further questions, please contact a healthcare professional.
What is Pradaxa inr?
Pradaxa, also known as Dabigatran, is a commonly prescribed anticoagulant in patients with atrial fibrillation, deep vein thrombosis (DVT) and pulmonary embolism (PE). Like the word anticoagulant suggests, Pradaxa is a medication that affects the coagulation cascade such that it prevents and reduces blood clot formation. Importantly, Pradaxa is a special kind of anticoagulant as it belongs to the Novel Oral Anticoagulant (NOAC) family. NOACs are different than traditional anticoagulants because they have a shorter half-life, rapid onset and more predictable pharmacodynamics. This is important when prescribing anticoagulants, because, unlike warfarin (a traditional anticoagulant), NOACs do not require constant monitoring to reach their optimal dose level. For example, the appropriate Dabigatran dose can be calculated by simply considering the patient’s comorbidities, age and condition; Dabigatran dose is not dependant on the individual’s genetic make-up.
Pradaxa dosing is even more advanced than other NOACs because it has the first and only FDA-approved reversal agent: Idarucizumab. This FDA approved reversal agent enables doctors to closely control Pradaxa dosing and its effects while reducing the general risks associated with taking a blood thinner. Moreover, enables a patient to have both Pradaxa and surgery (in theory).
Pradaxa Mechanism of Action
Pradaxa works by affecting a crucial step in the coagulation cascade: the binding of thrombin (an important enzyme) to its substrate (fibrin). It does this by directly binding to thrombin. Effectively, this prevents the conversion of fibrin to fibrin strands, which is important for the strength and the integrity of the blood clot. By preventing this reaction from going forward, Pradaxa can reduce the presence and the development of the clot. The extent of Pradaxa’s effect, however, is dependant on Pradaxa dosing. Furthermore, because Pradaxa specifically affects the binding of thrombin to its substrate in a reversible manner, clotting can be reversed by the addition of the humanized monoclonal antibody fragment Idarucizumab (Praxbind).
Pradaxa INR (Dabigatran INR)
A common measurement tool used to monitor blood thinners efficacy is; international normalized ratio (INR). The INR is essentially a calculation used to standardize prothrombin time (a test used to determine how fast blood clots). The calculation is important because different analytical systems used to make measurements can vary the results. Moreover, the INR calculation allows medical professional to effectively compare the prothrombin time in a patient receiving the blood thinner to normal mean prothrombin time. In general, the higher the INR, the longer it will take the blood to clot and the higher the risk of bleeding.
The INR of healthy people typically is 1.1 or below. In contrast, the INR range when using warfarin for disorders such as atrial fibrillation is 2.0 to 3.0. Notably, the INR range does vary with the disease being treated and the substance being used to treat the condition. This idea is further demonstrated by Pradaxa INR (Dabigatran INR). Because Pradaxa INR (Dabigatran INR) measurement is relatively insensitive to Dabigatran exposure, it cannot be used in the way it is for warfarin monitoring; typically, aPTT (activated partial thromboplastin time) is used for Pradaxa (dabigatran) monitoring. However, it is important to note that Pradaxa (dabigatran) monitoring is often not necessary; it is mainly used to measure and assess anticoagulant activity in patients using Pradaxa. INR measurements become important, however, when a patient is changing from warfarin to Pradaxa. It is often recommended that a patient starts Pradaxa dosing and discontinues warfarin at an INR of less than 2.0.
Pradaxa for PE (Pulmonary Embolism)
Deep vein thrombosis (DVT) and pulmonary embolism (PE) are both potentially dangerous conditions that involve blood clots. While DVT is associated with the development of blood clots in the deep veins (such as the leg), PE is associated with the lodging of blood clots in the lungs. Notably, both conditions are commonly referred to as a single condition called vein thromboembolism (VTE). This is because DVT often results in and is the cause of PE. It is extremely important to diagnose and treat both DVT and PE because they are often associated with medical emergencies. Together these conditions affect about 900,000 people in the United States every year.
There are many treatment options available for both PE and DVT, but an especially promising one is Pradaxa. When using Pradaxa for PE and Pradaxa for DVT, a patient can effectively reduce risk of reoccurrence with a similar efficacy as warfarin (RE-COVER trial). More importantly, Pradaxa for DVT and Pradaxa for PE provides doctors with the opportunity for Pradaxa reversal in the event of an overdose or an emergency. This is extremely important because anticoagulants have the potential to cause life-threatening bleeding. Moreover, prior to prescribing an anticoagulant, doctors often must balance the risk v benefit ratio. The ability to intricately control Pradaxa dosing and effects helps immensely in this balancing process. In general, the overall treatment goals associated with anticoagulant use include; 1) preventing the clots from growing, 2) reducing the risk of the clot moving to the lungs and 3) reducing the risk for reoccurrence of the medical condition.
Pradaxa for Afib (atrial fibrillation)
Pradaxa can also be used to treat atrial fibrillation (afib), a dangerous condition of the heart, that increases the risk of stroke. Afib occurs when one or both upper heart chambers (atria) beat in an irregular manner- they are not properly synchronized. The result of this is that blood pools in the atrium and it may increase the likelihood of clot formation. The obvious danger associated with blood clot formation in the heart is it may travel to other areas of the body and clog one of the arteries. Ultimately blocking off the artery, the organ will be depleted of oxygenated blood. Because the brain is one of the closest organs to the heart and it directly receives blood from the heart, it is very easy for one of its arteries to become closed. The devastating consequence may be ischemic stroke and any potential and permeant brain damage associated with it.
More than 2 million people in the USA are affected by afib each year, and it is most often treated by NOACs or traditional anticoagulants. Pradaxa for afib (atrial fibrillation) is especially promising, being the first FDA approved warfarin alternative in reducing the risk of stroke. Moreover, clinical trials have proven that Pradaxa is superior to warfarin in patients with non-valvar afib partly because of Pradaxa dosing and reversal.
Pradaxa Side Effects
Like most prescribed anticoagulants, Pradaxa side effects may include gastrointestinal bleeding, nausea, bruising, diarrhea and heartburn. Pradaxa side effects may be a result of interactions with certain foods or other medications. Some common interactions include; Advil, activase, cyclosporine, rifampin and aspirin. Alternatively, it may also simply be because Pradaxa is inhibiting the natural process of clotting; clotting is a mechanism used by the body to heal wounds and stop bleeding. This is an important consideration because if a doctor prescribes Pradaxa (or any anticoagulant), it is often because they believe that the benefits outweigh the risks. If you begin to observe these common side effects, please do not discontinue its use until you consult your doctor.
One of biggest risks associated with Pradaxa and many other anticoagulants is the risk of hemorrhages. However, unlike other NOACs, Pradaxa has a reversal agent that acts as an antidote. This essentially means that doctors can quickly mitigate the effects of Pradaxa in the event of an emergency, such as an injury resulting in heavy bleeding. This also means that combining Pradaxa and surgery would be ideal and not pose a problem as it would with other NOACs. Likewise, if a patient has an adverse reaction or experiences Pradaxa side effects, the drug can be sequestered to prevent its remaining effects.
How does Pradaxa Reversal Work?
As elucidated earlier, appropriate Pradaxa dosing and control is essential to reduce risks. If in the case Pradaxa dosing is not right for a patient, there are Pradaxa interactions or a patient would like to reduce Pradaxa side effects, Pradaxa reversal can help the patient return to normal clotting conditions. Idarucizumab (Praxbind) is an antibody fragment that binds specifically to Pradaxa. Importantly, Pradaxa has a 350 fold higher binding affinity for Praxbind than thrombin. This essentially means once Praxbind is administered, it will likely sequester most of the remaining Pradaxa and it will be in an almost irreversible manner. Once the complex forms, it can easily be eliminated by protein catabolism in the kidney. Effectively, the antidote can reverse Pradaxa without impacting the effect of other anticoagulants or thrombin.
For more information on the blood thinner pradaxa, such as information on pradaxa dosing and pradaxa side effects, please contact your local healthcare professional.