Highlights for warfarin
FDA Warning: Bleeding risk
- This drug has a Black Box Warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients to potentially dangerous effects.
- Warfarin thins your blood and limits your blood’s ability to clot. It can cause serious bleeding, which can lead to death. You must have regular blood tests and visits with your doctor to monitor your condition. Don’t start or stop any other drug or herbal product unless your doctor tells you to. Tell your doctor if you have any signs or symptoms of bleeding.
Other warnings
Bleeding problems warning: Tell your doctor if you have an increased risk of bleeding problems, such as being at least 65 years of age, having a history of heart attack or stroke, gastrointestinal bleeding, anemia, diabetes, or kidney problems. Your doctor will decide if warfarin is right for you.
Pregnancy warning: Don’t take this medication if you’re pregnant unless you have a mechanical heart valve. Warfarin may cause birth defects, miscarriage, or death of a fetus.
Calciphylaxis warning:This medication can cause calciphylaxis. This rare but serious condition is a buildup of calcium in small blood vessels. People with kidney disease are at greater risk for this condition.
Warfarin is a prescription drug. It comes only as a tablet you take by mouth.
Warfarin oral tablet is available as the brand-name drugs Coumadin and Jantoven. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in all strengths or forms as the brand-name drug.
Why it’s used
Warfarin is used to treat blood clots and to lower the chance of blood clots forming in your body. Blood clots can cause a stroke, heart attack, or other serious conditions if they form in your legs or lungs.
Warfarin is used to:
This drug may be used as part of a combination therapy. That means you may need to take it with other drugs.
How it works
Warfarin belongs to a class of drugs called anticoagulants. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.
Warfarin works by stopping your body from forming blood clots. It does this by blocking the formation of blood clotting factors, which are needed to make clots.
Warfarin oral tablet doesn’t cause drowsiness. However, it can cause other side effects.
More common side effects
The more common side effects that occur with warfarin are related to abnormal bleeding. Possible side effects include:
- unusual bruising, such as:
- unexplainable bruises
- bruises that grow in size
- nosebleeds
- bleeding gums
- bleeding from cuts that takes a long time to stop
- heavier than normal menstrual or vaginal bleeding
- pink or brown urine
- red or black stools
- coughing up blood
- vomiting blood or materials that looks like coffee grounds
Serious side effects
If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 911.
- Death of skin tissue. This may happen when blood clots form and block blood flow to an area of your body. Symptoms may include:
- pain
- color or temperature change to any area of your body
- Purple toes syndrome. Symptoms may include:
- pain and purple or dark color in your toes
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
Warfarin oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.
To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.
Examples of drugs that can cause interactions with warfarin are listed below.
Anticoagulants
Your risk of bleeding is increased when you take warfarin with anticoagulants. Examples are:
- Factor Xa inhibitors such as:
- apixaban
- edoxaban
- rivaroxaban
- Direct thrombin inhibitors such as:
Antiplatelet drugs
Your risk of bleeding is increased when you take warfarin with antiplatelet drugs. Examples are:
- P2Y12 platelet inhibitors such as:
- clopidogrel
- prasugrel
- ticagrelor
Nonsteroidal anti-inflammatory drugs (NSAIDs)
Your risk of bleeding is increased when you take warfarin with NSAIDs. Examples are:
- aspirin
- diclofenac
- ibuprofen
- indomethacin
- ketoprofen
- ketorolac
- meloxicam
- nabumetone
- naproxen
- oxaprozin
- piroxicam
Antidepressants
Your risk of bleeding is increased when you take warfarin with selective serotonin reuptake inhibitors (SSRIs) and serotonin and…
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