- Certain heart or blood vessel diseases
- Atrial fibrillation (abnormal heart rhythm)
- A heart valve replacement
- A risk of blood clots after surgery
- Congenital heart defects
- Anticoagulants make it harder for blood clots to form and include heparin, warfarin, dabigitran, apixaban, rivoroxaban, and edoxaban.
- Antiplatelets prevent blood cells called platelets from clumping together and forming a clot. Antiplatelets include aspirin and clopidogrel and are mainly taken by people who have had a heart attack or stroke.
There’s a lot you need to know when taking blood-thinning medications. Here are 16 dos and don’ts for staying safe and fully protected.
1. Do Watch Out for New or Increased Bleeding
“The main side effect of a blood thinner, not surprisingly, is bleeding,” says Christopher B. Granger, MD, a cardiologist at Duke Health in Durham, North Carolina.
The reason is that blood thinners are preventing your body’s natural ability to clot blood, which it does to stop bleeding and heal minor wounds.
So when taking a blood thinner, you might notice increased bleeding from cuts or scrapes, more frequent or more intense nosebleeds, or heavier-than-normal periods.
If minor bleeding bothers you, don’t stop taking the medication, says Mary Cushman, MD, the director of the University of Vermont Medical Center’s thrombosis and hemostasis program, in Burlington. Ask your doctor or pharmacist to recommend special wound dressings and other over-the-counter products that can help.
But if you notice blood in your urine, begin coughing up blood, vomit material that looks like coffee grounds (an indication of bleeding in the stomach), or have black bowel movements (a possible sign of bleeding in the digestive tract), call your doctor immediately, Dr. Cushman says.
2. Do Have Your Blood Checked as Often as Your Doctor Recommends
“Warfarin requires regular blood work to ensure you have the right dose, so your blood doesn’t become too thin or not thin enough,” says Cushman. “At the beginning, it can be two or three times per week. Once you’re stabilized, it’s usually every four weeks or so.”
Some of the newer drugs, which work on more closely targeted aspects of the clotting process, don’t require as much testing because they cause less bleeding, says Granger.
3. Do Tell Your Healthcare Provider About Any Other Medications You Take
Let your doctor, nurse, or pharmacist know about any prescription or over-the counter drugs, vitamins, and herbal supplements you’re taking.
Granger warns against taking aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) like naproxen and ibuprofen that can increase your risk of bleeding.
Different blood thinners react with different drugs.
- Aspirin
- Acetaminophen (Tylenol)
- Antacids or laxatives
- Nirmatrelvir/ritonavir (Paxlovid)
- Certain antibiotics
- Antifungal drugs such as fluconazole (Diflucan)
- Ibuprofen (Advil) or naproxen sodium (Aleve)
- Atrial fibrillation medications such as amiodarone (Pacerone, Nexterone)
- Anti-seizure drugs, including phenytoin (Dilantin, Phenytek), phenobarbital (Sezaby), carbamazepine (Carbatrol, Tegretol, Equetro)
4. Do Tell Your Doctor if You Plan to Stop Any Medication
Just as taking prescription and over-the-counter drugs can affect your blood-thinning medication, so can stopping them. It’s important to keep your doctor informed of any medication changes you’re considering.
5. Do Talk to Your Doctor About Different Dosages
Granger says that typically warfarin blood thinners are started on a lower dose and increased as necessary, as higher doses also increase the chance of excessive bleeding.
Very elderly people or those who have decreased renal or kidney function may be on a lower dose, says Granger. “Being on the correct dose is important.”
If you have concerns about your dose, talk to your doctor about adjusting your medication.
6. Do Consider Wearing a Medical Alert Bracelet
In case of an emergency — such as a car accident — it’s important that healthcare providers know you’re taking a blood thinner, which can raise your bleeding risk and potentially change your recommended treatment.
Devices like the Apple Watch and Fitbit have apps that can check your heartbeat and rhythm for atrial fibrillation (a possible complication of atrial fibrillation is blood clotting). If a device identifies possible irregular heartbeats, schedule an appointment with your physician.
7. Do Plan Ahead for Travel
If you plan on taking a trip, get your doctor’s okay for traveling, advises Michael Zimring, MD, a specialist in travel medicine at Mercy Medical Center in Baltimore. Then research your destination: Learn where the nearest hospital or clinic is in case you run into a situation that causes excess bleeding or you’re in need of emergency blood work.
8. Don’t Sit Too Long
A blood thinner makes it less likely that you’ll get a clot, but “it’s still smart to get up and move around every hour or two,” Dr. Zimring says.
What if you’re stuck in your seat for a while?
“Lift your legs up and down, pump your calves, point and flex your toes — do anything you can to get the blood flowing,” he says.
9. Do Be Consistent With Vitamin K Intake
Warfarin works by reducing the clotting effects of vitamin K, which is found in many green vegetables, including kale, broccoli, Brussels sprouts, and collard and mustard greens. So if that’s the medication you’re taking, eating too many of these foods at once could reduce its effectiveness, Cushman notes.
But if you eat moderate amounts of green vegetables every day, your doctor can take that into account when determining the dosage you need, she adds. It’s not about avoiding these foods so much as staying consistent with how much you consume, because your dose of blood thinner is calibrated accordingly.
“If you binge on a big spinach salad one day, you might have problems,” Cushman says. “But if you eat salad every day and don’t vary it, you’ll be stable. You don’t have to totally block [these foods] out.”
10. Do Drink Plenty of Water
What’s more, a full bladder will prompt you to get up regularly to use the restroom, helping prevent long periods of sitting, Zimring adds.
11. Do Seek Care Immediately if You Fall or Hit Your Head
Even if you aren’t visibly injured, you could be bleeding internally, especially if you hit your head, the AHRQ notes. And a bruise is a sign that you’re bleeding beneath the skin.
12. Don’t Worry Too Much About Shaving
People on blood thinners are often fearful of cutting themselves while shaving, but “you won’t bleed to death from a nick,” Cushman says.
If shaving any part of your body stresses you out, switch to an electric razor or a different hair-removal method.
13. Don’t Drink Excessive Amounts of Alcohol
Drinking to the point of intoxication also increases your chances of falling or having an accident, adds Cushman.
14. Don’t Necessarily Stop Your Blood Thinner Before a Dental Procedure
Talk to your doctor about whether or not to stop taking your blood thinner for dental procedures. And let your dentist know what drug you’re taking and what your doctor has advised.
The risks of stopping your blood thinner “far outweigh the consequences of prolonged bleeding, which can be controlled,” the ADA says.
15. Don’t Double Up on Missed Doses
You should try to take your blood thinner at the same time each day, in accordance with your doctor or pharmacist’s instructions. But if you forget a dose, resist the urge to make up for it with a double dose next time.
16. Don’t Be Afraid to Stay Active
Staying physically active is healthy, so don’t stop your favorite exercise routines because you’re using blood thinners.
“Not only can you, but you should stay active,” says Granger. “Now, I wouldn’t do anything crazy like jump out of airplanes or get into a boxing ring, but most things are okay.”
Low-impact activities such as walking, biking, yoga, Pilates, and strength training should be fine. But if you enjoy higher-intensity sports that pose a greater risk of injury, ask your doctor if they’re safe for you.
The Takeaway
- Blood thinners play a critical role in preventing serious events such as strokes and heart attacks by managing the formation and expansion of blood clots.
- Regular blood work to monitor the effects of blood thinners is essential, especially if you’re taking medications like warfarin, which require precise dosing to avoid risks like excessive bleeding.
- Be sure to let your healthcare provider know about all medications, supplements, and vitamins you’re taking, as they can interact dangerously with blood thinners.
- If you experience severe bleeding signs such as blood in the urine or vomit, seek immediate medical attention to address potential side effects related to blood thinner use.