Q: My father takes a blood thinner called warfarin and my husband takes aspirin. My father says he has to have blood tests all the time but my husband doesn’t. Don’t all blood thinners work the same?
Blood thinners can work in different ways because our body uses two different ways to stop us from bleeding. One type of blood thinner works on one of those ways, and the other type works on the other way.
Warfarin and aspirin are called blood thinners because they work to make it harder for our blood to clot, and that causes more blood to leak out of cuts and scrapes. By slowing down the clotting process, a blood thinner makes us bruise easily if we bump ourselves and to bleed more freely and longer when cut or punctured.
Your body has a special system to call for help when you are injured. There is a trigger chemical that lies right underneath the lining of each of your blood vessels, covered up like a bedspread covers up the sheets on a bed. Blood will flow smoothly through your blood vessel as long as the lining of your blood vessel (the bedspread over the sheets) is not disturbed.
When your blood vessel is cut, crushed or torn, it’s like pulling the bedspread up off the bed and showing the sheet underneath. The trigger chemical (the sheet) comes in contact with the blood and starts a chain reaction designed to stop blood from leaking out from that damaged area, eventually forming a clot.
There are 2 stages to this reaction: a rapid response and a slower one. The rapid response slows down the blood flowing through the damaged area and blocks the hole so less blood leaks out. This occurs rapidly from contact with the trigger chemical, which makes clear cells in your blood called platelets get “sticky” and clump together around the damaged area. Like rocks in a stream, these clumps of cells work to slow down the flow of blood and decrease the amount of blood leaking out of your cut or puncture.
The clot is formed by the slower process which eventually stops the bleeding completely instead of just slowing it down. There are 10 or so compounds in your body called clotting factors that work together to seal up leaks in your blood vessels. Until they are needed, these clotting factors just float around in your blood in a form of storage. They are always available but not active until something triggers them to change.
When one of your blood vessels is cut or torn, the trigger chemical inside its lining is in contact with your blood and starts a chain reaction of your clotting factors. As they flow by the injury they change into an active shape and work together to form a secure seal or blood clot over the leaking blood vessel. This takes about 12 seconds in most people.
Aspirin works as a blood thinner by permanently changing the platelets in your blood so that they can’t clump up. You must make new platelets without being on aspirin for its effect to wear off, which takes about a week. This is why many surgeons instruct you to stop aspirin 1 week before an upcoming procedure or a colonoscopy.
Warfarin also works as a blood thinner, but in a different way. Instead of affecting your platelets, it interferes with the way your clotting factors work together to seal up the leak in a blood vessel. Warfarin dosing is complicated and regular blood tests need to be done to make sure you are getting the right amount for you.
The higher the dose of either warfarin or aspirin the more they slow down the clotting process and the higher the chance you could experience serious bruising or life-threatening bleeding. Taking both aspirin and warfarin at the same time can be dangerous and should only be done if directed by a physician or medical provider and under their regular supervision.
