A blood thinner slows down the blood's ability to form clots. This helps prevent clots that can cause life-threatening problems such as stroke, heart attack, and pulmonary embolism. These medicines also can keep blood clots from getting bigger.

Blood thinner medicines work in different ways to prevent blood clots. But all of them raise the risk of serious bleeding. This can happen from an injury, or it can occur suddenly inside your body.

Blood thinners include medicines called antiplatelets and anticoagulants.

Antiplatelets

Examples include:

• Low-dose aspirin.
• Clopidogrel (Plavix).
• Prasugrel (Effient).
• Ticagrelor (Brilinta).

Anticoagulants

Examples include:

• Enoxaparin (Lovenox).
• Dabigatran (Pradaxa).
• Rivaroxaban (Xarelto).
• Warfarin (Coumadin). To learn more about warfarin, see Warfarin: Taking Your Medicine Safely.

Continue to Why?

Blood thinners make your blood take longer than normal to clot. This can cause serious bleeding.

When you take blood thinners, bleeding problems can happen when you:

• Fall or are injured. An injury can cause bleeding that is hard to control.
• Take other medicines. Taking certain other medicines along with a blood thinner can raise your risk of bleeding.
• Have surgery or some procedures. These can raise your risk of bleeding too much.

Bleeding also can happen inside your body without an injury when you take blood thinners.

Continue to How?

You can take blood thinner medicine safely by taking a few steps:

1. Know the signs of bleeding.
2. Tell your doctors and dentist about all the medicines you take.
3. Talk to your doctors about surgeries and tests.
4. Prevent falls and injuries.

1. Know the signs of bleeding.

Call 911 if:

• You cough up blood.
• You vomit blood or what looks like coffee grounds.
• You pass maroon or very bloody stools.
• You have a sudden, severe headache that is different from past headaches. (It may be a sign of bleeding in the brain.)

Call your doctor right away if:

• You have new bruises or blood spots under your skin without a known cause. (With shots, bruising is normal around an injection site.)
• You have a nosebleed that doesn't stop quickly.
• Your gums bleed when you brush your teeth.
• You have blood in your urine.
• Your stools are black and look like tar or have streaks of blood.
• You have heavy period bleeding or vaginal bleeding when you aren't having your period.

If you are injured, apply pressure to stop bleeding. Realize that it will take longer than you are used to for the bleeding to stop. If you can't get the bleeding to stop, call your doctor.

2. Tell your doctors about all your medicines, and take your medicines properly.

Give your list of medicines to every doctor and dentist who treats you. Taking certain medicines along with a blood thinner can cause bleeding. It also can change how well your medicines work.

To avoid problems:

• Tell your doctor about all of the prescription medicines, over-the-counter medicines, antibiotics, vitamins, and herbal products that you take.
• Make and go to all your appointments for checkups or tests. Call your doctor if you are having problems with your medicine.
• Don't take aspirin and other pain relievers, such as ibuprofen (for example, Motrin), unless your doctor tells you to take them and when and how to take them.
• Take your medicine at the same time of day, as prescribed.
• If you take several medicines, use a daily medicine planner to keep track of them. It's a list of every medicine and vitamin you take, along with when and how often you take each one. You can make your own list or use this medicine planning sheet (What is a PDF document?).
• Store your medicine the right way. A few medicines must be stored in their original containers so they don’t spoil. If your medicine label has this instruction, then don’t use a pillbox for that medicine.
• Know what to do if you miss a dose of your blood thinner.

For information about taking aspirin safely, see Low-Dose Aspirin Therapy.

3. Talk to your doctors about surgeries and tests.

Check with your doctor as soon as you can before any surgery or test (such as a colonoscopy). You may need to stop taking your blood thinner or some of your other medicines up to a week or more before the procedure. Your doctor will tell you when it is safe to start taking your medicine again.

4. Prevent falls and injuries.

If you have a high risk of falling, make these changes in your life to prevent falls:

• Wear slippers or shoes that have nonskid soles.
• Use a cane or walker if you need one.
• Put things within easy reach so that you don't need to reach over your head for them.
• Keep a cordless phone and a flashlight with new batteries by your bed.

Make these changes in your home to prevent falls:

• Remove raised doorway thresholds, throw rugs, and clutter.
• Rearrange furniture and electrical cords to keep them out of walking paths.
• Keep stairways, porches, and outside walkways well lit. Use night-lights in hallways and bathrooms.
• Install sturdy handrails on stairways. Install grab handles and nonskid mats inside and outside your shower or tub and near the toilet.
• Add extra light switches if needed or use remote switches, such as sound-activated switches, on lights by doors and near your bed. Then you won't have to get up quickly to turn on the light or walk across the room in the dark.
• Repair loose carpet or raised areas in the floor that may cause you to trip.
• Use shower chairs and bath benches.
• Use nonskid floor wax. Wipe up spills right away, especially on ceramic tile floors.
• If you live in an area that gets snow and ice in the winter, have a family member or friend sprinkle salt or sand on slippery steps and sidewalks.

To prevent injuries, be careful with your activities:

• Choose activities that have a lower risk of injury, such as swimming and walking. Try to avoid activities or sports that put you at risk of injury. But if you take part in activities that carry a risk of falling or injury, be as safe as possible and wear protective equipment, such as helmets.
• Be extra careful when you work with sharp tools or power tools, such as saws.
• Use an electric razor, not a razor blade.
• Use waxed dental floss and a toothbrush with soft bristles.
• When you work outside, wear clothing that protects you, such as gloves, shoes, and long sleeves.

Continue to Where?

Now that you have read this information, you are ready to make sure you are taking your blood thinner medicine safely.

Talk with your doctor

If you have questions about this information, print it out and take it with you when you visit your doctor. You may want to mark areas or make notes where you have questions.