Injuries and blood thinners: How to stop bleeding

Blood thinners are medications that make it harder for blood clots to form. Such clots can cause heart attacks, strokes, or leg vein clots that travel to the lung — all dangerous conditions. If you are at extra risk for these conditions, taking a blood thinner can reduce that risk (see "How blood thinners work").

But the anti-clotting action also puts you at risk for uncontrolled bleeding if you get injured. "It takes longer for any bleeding, even a small amount, to stop when you're on these medications," says Dr. Kei Ouchi, an emergency physician at Harvard-­affiliated Brigham and Women's Hospital.

Take the time now to learn how to respond to bleeding that can result from a number of scenarios.

A minor cut or scrape

A minor cut or scrape isn't usually an emergency. The blood oozes out slowly, and you have plenty of time to stop it, even if you're on a blood thinner.

First, hold the wound under running water to rinse out debris. "Don't use hydrogen peroxide. That might slow or impair healing," Dr. Ouchi says.

Next, apply pressure — lots of it. "Cover the wound with your fingers or use a tissue, gauze pad, or clean cloth, and press hard," Dr. Ouchi says. "If blood still leaks out, you're not applying enough pressure. You'd be surprised how much pressure it takes. It should hurt a little."

The same principle applies if you have bleeding gums or a nosebleed, which might develop from a small cut or as a side effect of the blood thinner. Press on your gums or pinch the bridge of your nose as hard as you can for at least 10 minutes (continuously).

If the wound is on an arm or leg, raise the injured limb into the air (while applying pressure on the wound), allowing gravity to help slow blood flow to your wound.

Don't worry if it takes a long time or if the wound area (such as a finger) turns blue. "It would take four to six hours for any lasting damage to occur, and you won't need that much time. Keep applying pressure until you stop bleeding, then cover the wound with a bandage," Dr. Ouchi says.

If the bleeding doesn't stop or the wound needs stitches, go right to a hospital emergency department. Tell the staff that you're on a blood thinner.

For serious cuts or injuries

Serious injuries, no matter the size, don't ooze blood — they gush, most likely because there's damage near an artery. The heart keeps pumping, blood pours out, and the blood thinner you're taking only makes it worse. This is a life-threatening situation and warrants an immediate call to 911.

Until paramedics arrive, apply as much pressure as possible to the wound. If the injury is on an arm or leg, tie a tourniquet as tightly as possible just above the wound. Raise the injury up high, above your heart.

If the wound is on your torso, place a clean cloth on it and press it as hard as possible. Don't let up on it.

Once you're at a hospital, the staff needs to know that you're on a blood thinner. "The fastest way to alert everyone is by wearing a medical bracelet. That's especially helpful if you are unconscious," Dr. Ouchi says. (You can get a bracelet with the words "blood thinner" online for less than $10.)

The medical team will know how to stop the bleeding and may give you a blood thinner antidote.

For internal bleeding

You can't tell when an accident causes internal bleeding in your head or anywhere else in your body (like your belly or chest). So if you're on a blood thinner and you're injured or hit your head from a fall or an accident, go to the emergency department to get checked out at the first sign of trouble (such as headache, trouble seeing, confusion, nausea, or lightheadedness).

Tell the staff you're on a blood thinner. If the doctor orders imaging tests, and they're clear, you may not be out of the woods just yet. "If you hit your head, there's a small chance that you'll have delayed bleeding that can take days or weeks to cause symptoms," Dr. Ouchi says. "If you feel worse after your initial evaluation — if you get a bad headache, you're vomiting, or you develop confusion — come back to see us as soon as possible, so we can re-evaluate and treat you."

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