Oral Anticoagulants and Getting Old
There are a number of diseases that have as their final fatal or major clinical problem the formation of a clot. A clot is coagulation of our blood in one of our many, many vascular locations. Ordinarily, blood does not clot and this is why blood flows freely to all our organs and tissues. It is not normal to have coagulation in our arteries or veins. It is however, normal to form clots when we are cut or bruised. In fact, that is why we do not blood to death when we have a laceration or any kind of injury that disrupts the normal blood vessels.
When Clotting Occurs and Shouldn't
From the introduction above it is apparent that we are not supposed to have coagulation occur in our veins and arteries. However, in certain situations and diseases the body does form clots in vessels. The result can be fatal as in a heart attack or disabling in the case of a brain stroke. In some people who sit for long times, as in intercontinental plane travel, or after surgery when we are confined to bed, blood in the veins (particularly those deep in the leg) can clot. These clots form more, bigger clots and these clots can move from their source through the heart to the lungs causing "pulmonary embolism" that can be fatal or debilitating. A final abnormal event that causes blood to clot is the heart arrhythmia called atrial fibrillation. In this condition the blood is not mixed well in the atria of the heart and can clot and be pumped into the brain to cause a stroke.
What Is Done to Prevent Abnormal Clotting
There are a number of medicines that all work in different ways that can be given to patients to prevent the clots in vessels. These drugs as a group are called anticoagulants. We could write pages about these varied drugs, but most of them fall into two categories, those given by injection and those taken by mouth. It is the ones taken by mouth that are usually used by patients for a long time and we will concentrate on three of the most commonly used oral anticoagulants.
Aspirin has many uses and everyone who is reading this knows about the uses of aspirin as an analgesic or to reduce a high fever. But, it also has mild anticoagulant effects. Aspirin interferes with platelet aggregation that is necessary in forming a clot. For this reason aspirin is prescribed by physicians to prevent stroke, heart attacks and some other clotting problems. Aspirin is not as "strong" as two other commonly used anticoagulants in preventing blood clots.
The oldest stronger anticoagulant is Coumadin or warfarin (used historically to kill rats) that interferes with Vitamin K. Vitamin K is required to cause clotting and warfarin blocks this action, so patients do not clot normally. The drug has been used for a very long time and has proven effective in preventing strokes and deep vein thrombosis that cause pulmonary embolism. Warfarin is not as predictable nor as easy to regulate as aspirin and many foods interfere with its actions like green leafy vegetables and, naturally, anything with Vitamin K in it. Patients on warfarin must have a blood test (a PTT) run often to be sure the dosing is appropriate.
The newest oral drug available for anticoagulation is revaroxaban (Xarelto) that is as effective as warfarin and much easier to maintain dosage. This drug is a direct inhibitor of factor Xa needed to cause a clot. The drug does not require monitoring (since there is no test to measure its action). There is no antidote for it as there is for warfarin (Vitamin K), and if severe bleeding occurs there is no treatment except transfusion.
Side Effects of Anticoagulants
Because all three of these drugs inhibit clotting. some of the side effects are unintended bleeding. The bleeding can be on the face when cut shaving, for example, or bleeding into the brain causing a stroke. Bleeding can also occur in the stomach/intestine, lungs, kidneys, nose or other places. Bruising is much more prominent and common when we are on these medicines. When taking the medications it is important for the patient to watch for any blood coming from the organs or other sites as well as large bruises under the skin.
Indications for Anticoagulants
These drugs are used to prevent heart attack, stroke, pulmonary embolism and deep vein thrombosis. They are effective but can only be started by your physician, who needs to monitor your coagulation along with your own vigilance for unusual bleeding. Because the older we get the more prone we are to have problems with coagulation, too much or too little, it is likely that we will be taking an anticoagulant. Anticoagulant therapy is just one more way for us to age with better health, but it carries risks that we all need to be mindful of.
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