Blood Thinners: Uses, Types, Side Effects

Blood thinners prevent blood clots, which can stop blood flow to the heart. They are medications taken orally or intravenously (through a vein) to prevent a blood clot. Blood clots can stop the flow of blood to the heart, lungs, or brain. They can cause a heart attack or stroke.

Your doctor may recommend taking a blood thinner if you have heart disease, including heart valve disease, and irregular heart rhythms.

Blood thinners must be taken exactly as directed. When you don’t take enough, the medication won’t be as effective. Taking too much can lead to severe bleeding.

What blood thinners do

Some blood thinners thin the blood to keep blood cells from sticking together in the veins and arteries. Others prevent blood clots by increasing the amount of time it takes for blood clots to form. These are known as antiplatelet and anticoagulant drugs respectively.

Antiplatelet drugs prevent blood cells (called platelets) from clumping together and forming clots. Examples of antiplatelet drugs are:

  • Aspirin
  • clopidogrel (Plavix)
  • dipyridamole (Persantine)
  • ticlopidine (Ticlid)

Doctors often prescribed medications called anticoagulants to people who have been diagnosed with some forms of heart disease. “Coagulate” is a medical term that means “to clot.” These blood thinners prevent blood clots by increasing the amount of time it takes your blood to clot.

Anticoagulants prevent clots from forming. Common anticoagulant blood thinners include:

  • warfarin (Coumadin, Jantoven)
  • enoxaparin (Lovenox)
  • heparin

Newer anticoagulants with less risk of bleeding include:

  • dabigatran (Pradaxa)
  • apixaban (Eliquis)
  • rivaroxaban (Xarelto)

Your doctor will carefully monitor your dosage of blood-thinning medication. They may occasionally run a prothrombin time (PT) test for some medications. This blood test measures your international normalized ratio (INR).

INR is the rate at which your blood clots. An appropriate INR rate varies from person to person according to their medical history. Staying within your INR range can prevent you from bleeding excessively or clotting too easily.

Possible side effects

Blood thinners may cause side effects in some people. Excessive bleeding is the most common reaction. It can occur in a variety of ways, including:

  • heavy periods
  • bloody or discolored urine or feces
  • nosebleeds
  • bleeding gums
  • prolonged bleeding from a cut

Other side effects can include:

  • dizziness
  • muscle weakness
  • hair loss
  • rashes

The presence of blood thinners in your system can increase your risk of internal bleeding after an injury. Go to the hospital right away if you experience any of these side effects after falling or bumping your head — even if you don’t have external bleeding.

Your doctor may tell you to limit your participation in contact sports to reduce the risk of bleeding. However, this doesn’t mean you can’t exercise or live a normal life. Swimming, walking, and jogging are excellent forms of exercise and are safe for most people taking anticoagulants. Discuss with your doctor which types of exercise may be best for you.

Tell your dentist that you’re taking blood thinners to avoid excessive bleeding during regular teeth cleanings.

It’s also important to protect yourself when using knives, scissors, or yard equipment.

Possible drug interactions

Various foods, herbs, and medications can interfere with blood thinners. These substances can make the drug more or less effective than your dosage would suggest. However, not all blood thinners are affected by the same substances. It’s important to speak with your doctor or cardiologist about your diet and how it may impact the effectiveness of your medication.

These interactions may include:

  • Vitamin K, such as cabbage, brussels sprouts and broccoli
  • Herbs, including chamomile, echinacea, clove and evening primrose oil
  • Medications, like antibiotics, antifungal drugs, pain relievers, and acid reducers


Keyword: blood thinners.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.