Should I still take my rat poison? This is a common question I receive from my patients but also from audience members during my presentations on stroke treatment and prevention.
Coumadin, also known as warfarin, has been a very effective tool in pest control. The reason it works so well is that it keeps animal’s, and therefore, people’s blood from clotting. Over time it accumulates in the rat’s system and when it bumps itself; unable to stop the bleeding, it bleeds to death. So why should a person take such a horrific sounding chemical? The reason is that not clotting can be advantageous in the right situations. It has been shown in several medical studies, including the SPAF (Stroke Prevention in Atrial Fibrillation) studies, that people who suffer from a specific heart rhythm problem, atrial fibrillation, that very specific levels of blood thinning using Coumadin significantly reduces the risk of stroke. The problem mainly arises with keeping the blood thinning, also known as level of anti-coagulation, at the right level. If the level is too low the risk of stroke is high, and if the level is too high then the risk of bleeding is high. The bleeding can take place in any part of the body but the most dangerous place for this to occur is in the brain, called an intracranial hemorrhage, or the gut, called a GI, gastro-intestinal, bleed.
Because of these risks the level needs to be checked often. This means getting frequent blood tests. It also means adjusting your diet. The reason for this is that Coumadin specifically inhibits the actions of Vitamin K. Vitamin K helps the body form clotting factors. When the level of Vitamin K is not kept constant over time, Coumadin can either have too much or too little effectiveness, leading to bleeds or clots. Often people are instructed to avoid foods with Vitamin K to avoid the potential for this problem. Unfortunately, the foods that contain Vitamin K are often vegetables. Avoiding these foods can lead to other health problems over time. I take a different approach and choose to take the time and resources to educate patients on Coumadin how to eat a Vitamin K equivalency diet. This entails teaching people how to eat a proper diet and to make sure that over time the amount of Vitamin K they eat is constant. Another problem with taking Coumadin is that it can interact with other medications, herbs, or hormones, resulting in adverse side effects. Up until recently this has been how people with atrial fibrillation and a high risk of stroke have been treated. As a result of the release of new drugs such as Pradaxa and Arixtra, also known as Novel Anticoagulants (NoA), there has been a change in how patients with atrial fibrillation can be treated. NoAs are pills that act as an anti-coagulant but has the advantage of being dosed at a constant level lessening the need for constant blood tests. However, it still has the risk of bleeding. A problem that may arise from taking a NoVA is that it is difficult to test for in the acute setting. This has relevance for people who show up to an emergency room with an acute stroke and are taking a NoA. If the treating physicians are not aware of this exposure the person may be given a medication, tPA (tissue plasminogen activator), that breaks up clots in the brain. The combination of a NoA and tPA could lead to a devastating outcome: intracranial hemorrhage and death. I often advise patients taking a NoA to wear a medic alert necklace or bracelet indicating the exposure to an anticoagulant.
About the author: Dr. Aaron Heide is a neurologist with offices in Enumclaw and Bonney Lake.