Anticoagulants—more widely known as “blood thinners”—are used in patients with cardiovascular disease. Blood thinners don’t actually thin the blood; they interfere with the ability of a protein called fibrinogen that causes blood to clot. This makes them useful for preventing blood clots from forming in the arteries or veins, where they could cause a heart attack or stroke or blood clots in the legs or lungs.
But taking a blood thinner requires some work, since it is necessary to maintain enough drug in the blood to prevent unwanted blood clots without increasing the risk of bleeding.
“The main side effect of blood thinners is unwanted bleeding, which can occur anywhere in the body. The most feared side effect is bleeding in the brain, which is a intracerebral hemorrhage, or stroke,” says vascular medicine specialist John Bartholomew, MD, Director of the Thrombosis Center at Cleveland Clinic.
Fear of unwanted bleeding causes some people excessive worry when a blood thinner is prescribed. If this sounds like you, be reassured that the benefits of the drug outweigh the risks.
“A blood clot can travel to the brain or lungs and kill you without warning,” says Dr. Bartholomew. “On the other hand, unwanted bleeding generally only occurs following an injury or trauma such as a car accident, or if the patient has a lesion such as a stomach ulcer orpolyp.”
Until recently, the only blood thinner for outpatient use was warfarin (Coumadin). Patients on warfarin require regular blood tests to ensure they are maintaining adequate blood levels of the drug. They cannot take certain antibiotics or antifungal agents that interfere with warfarin’s effectiveness, and they have restrictions on certain foods that contain vitamin K, such dark, leafy greens, for the same reason.
That’s why patients and physicians alike were relieved when a new class of blood thinner was introduced. These drugs are known as direct oral anticoagulants (DOACs), new oral anticoagulants (NOACs) or target-specific oral anticoagulants (TOACs). To date, four have been approved by the FDA: dabigatran (Pradaxa), apixaban (Eliquis) rivaroxaban (Xarelto) and edoxaban (Savaysa).
There are no food restrictions with DOACs, and drug-drug interactions are rare. DOACs don’t require monitoring, either, so taking them doesn’t require much thought. However, that doesn’t leave all patients off the hook. “Guidelines suggest blood work be done at least once a year on all patients and twice a year on patients who are elderly or have kidney disease,” says Dr. Bartholomew.
And because DOACs are so easy to use, doctors worry some patients may forget to take their medication. “If you miss a dose, it’s out of your system a lot more quickly than warfarin, and your risk of clotting increases,” he says.
When DOACs Are Preferred
DOACs can be used to treat clots in the lungs (pulmonary emboli) or legs (deep-vein thrombosis) and prevent them from recurring. They are also used to reduce the risk of clots in patients with atrial fibrillation not caused by a valve problem or to prevent blood clots after orthopedic surgery; surgery of the chest, abdomen and pelvis; or neurosurgical procedures.
When Warfarin Is Best
Despite its inconveniences, warfarin remains the blood thinner of choice for certain patients, including thosewith:
– Kidney or liver disease.“DOACs are metabolized in the kidneys, and poor kidney function could cause drug levels to build up to high levels,” Dr. Bartholomew explains.
– Mechanical heart valves. Warfarin is simply more effective than DOACs in preventing clots from mechanical valves.
– Clotting conditions known as thrombophilia or hypercoagulable states.“This is an area of ongoing research,” says Dr. Bartholomew.
Reversing the Drug
One of the most valued properties of warfarin has been the availability of an antidote. If unwanted bleedingoccurs, warfarin’s blood thinning capability can be immediately reversed to stop the bleeding.
At this time, dabigatran is the only DOAC with an FDA-approved antidote.
However, antidotes for the other DOACs will likely be approved this spring, leveling the playing field for all four blood thinners.
No matter which blood thinner you take, Dr. Bartholomew says you shouldn’t keep it a secret. There may be a time doctors need to know you are on a blood thinner “Keep a card in your wallet or wear a bracelet saying you are on a blood thinner, and which one,” he advises. “If you are knocked unconscious and taken to the emergency department, this information could save your life.”
Pulmonary Embolism: A Deadly Blood Clot
Pulmonary embolism (PE) is the third most common cardiovascular cause of death after heart attack and stroke, yet many people have never heard of it.
A PE occurs when a blood clot travels to the lungs from somewhere else in the body—mostoften a leg vein—and blocks blood flow to the arteries of the lungs.
Heart diseases, certain forms of cancer and surgery are common causes of blood clots. That’s why blood thinners are often prescribed for patients with these diseases.
Blood clots can also arise in people who are sedentary, which is why people are advised to get up and walk periodically when flying or driving long distances.
Symptoms of a Blood Clot in the Lungs
The most common symptoms of PE are:
– Sudden shortness of breath
– Chest pain that worsens with exertion but does not resolve with rest, or feels worse when you breathe in
– A cough that produces bloody sputum
– Passing out or almost passing out.
If you experience any of these symptoms, call 911. PE is a life-threatening medical emergency.
Symptoms of a Blood Clot in the Legs
The most common symptoms of a blood clot in the legs are:
– Significant swelling in a leg
– Pain or tenderness in the swollen area
– Warmth or redness in the swollen area
– Red or purple skin near the swelling.
If you experience these symptoms, contact your physician immediately.