Ask the doc: Does taking blood thinners mean I shouldn't ride?

People are living longer and medicine keeps getting better at managing their conditions while they do so.

Fast food, lifestyle choices, work pressures, and a sedentary lifestyle for many have contributed to the obesity epidemic. Heart attack, abnormal heart rhythms and strokes are increasingly common. Advanced care for medical and surgical procedures has increased, and the risk of clots in veins in the legs and the pelvis also appear to be increasing.

What does this have to do with riding? Lots! More people are taking medications that interfere with how blood clots. Blood thinners are useful for treating these medical conditions.

JD Power data pegs the average age of the U.S. motorcycle rider at 47 years. Nearly 40 percent of U.S. riders are in the 51-69 age bracket. That group is in the crosshairs for the use of medications that thin the blood as part of life-saving care.

Say you finally went to that adventure camp training you’ve been dreaming of. It was great until the part where you had to turn around the behemoth BMW you rented on a steep hill. Unlike the instructor’s graceful navigation, somehow your bike rolled down the hill and over you, shattering your hip and pride. No worries. Your hip was replaced and you are ready for discharge.

But wait, you now have a new medication — warfarin (tradename: Coumadin). And you will still be taking it when you start riding on the street again. Warfarin is one of a host of medications that make it harder for your blood to clot (you can also find it in rat poison — really). We use this medication in a controlled fashion to keep people from forming clots in both veins and arteries, especially when they are more stationary than usual, such as after surgery.

blood clot

Clots contain red blood cells, a protein called fibrin that acts as a scaffold, and platelets that cause everything to clump together in a contained mass. Making your blood thin interrupts that normal process.

Blood thinners come in two flavors — those that interfere with enzymes dependent on Vitamin K, and those that act directly (aka Direct Oral Anti-Coagulants, DOACs). Blood thinners are not the same as antiplatelet agents like aspirin or clopidogrel (trade name = Plavix). However, platelets and blood enzymes that produce fibrin all work together to create a stable clot.

It is important to note that diet is very important when taking Coumadin, because changes in Vitamin K intake (green leafy vegetables, like spinach) affect how well Coumadin thins your blood. For other agents, especially Plavix, your genetics can make the medication less effective. These are things your doctor will monitor.

So does this mean you can’t ride?

It is easy to imagine how these medications might not be ideal after a motorcycle crash, or even slicing a roll while making lunch. Bleeding, and lots of it, generally follows as your clotting enzymes (factors) can no longer work together in a normal way with platelets.

There is little data about how motorcycle riders fare if they crash and are on these medications. There is a lot of data for auto occupants, and even more for those who fall.

In those groups, patients who have serious injuries generally need more blood transfusions, have longer hospital and ICU stays, and have more complications than those who are not anticoagulated. While the blood supply is the safest it has ever been, getting someone else’s blood still carries risks, too.

The type of anticoagulant matters as well. A recent Journal of Trauma and Acute Care Surgery study found that patients on DOACs compared to those on Coumadin were more likely to survive after blunt head trauma with bleeding into or around the brain. While it was not focused on motorcyclists, the data is suggestive, even though the anticoagulant effects of most DOACs are difficult to reverse. Only one DOAC has a specific reversal agent (dabigitran is reversed by idarucizumab, an engineered monoclonal antibody; yes, doctors have issues pronouncing it too). Warfarin and the antiplatelet agents are much more readily reversed with clotting enzymes and Vitamin K or platelet transfusion.

What does this mean for you? It does not mean that you need to stop riding. It does mean you should specifically discuss riding with your doctor.

Understanding the bleeding risks should also help you decide how much protective gear you should wear. Road rash is a vast open wound from which you may freely bleed in large quantity. Armor (including a helmet) will reduce the transmission of blunt forces to your organs, potentially reducing the extent of injury and the bleeding that follows, perhaps most importantly in or around your brain.

Medicine is better than ever at keeping people from clotting. That’s a good thing right up until it isn't.

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