Warfarin (oral route)

What is Warfarin?

Warfarin is an anticoagulant (“blood thinner”) used to prevent and treat blood clots such as:

• Deep vein thrombosis (DVT)
• Pulmonary embolism (PE)
• Clots related to certain heart conditions
• Clot prevention after heart attack or heart surgery

It works by reducing the blood’s ability to clot.

Important Precautions

• Warfarin requires regular blood tests (INR tests) to ensure safe and effective dosing.
• Take the medication exactly as prescribed.
• Do not stop or change the dose without consulting your doctor.
• Consistency in Vitamin K intake is very important because Vitamin K can affect how warfarin works.

Foods High in Vitamin K

Avoid sudden changes in intake of:

• Spinach
• Broccoli
• Cabbage
• Brussels sprouts
• Green leafy vegetables
• Soybean and canola oils

Drug & Food Interactions

Warfarin interacts with many medications, supplements, and foods.

Common medicines that may increase bleeding risk:

• Aspirin
• Ibuprofen and NSAIDs
• Heparin
• Clopidogrel
• Some antibiotics and antifungals

Herbal supplements that may interact:

• Garlic
• Ginkgo
• Ginseng
• St. John’s Wort
• Turmeric

Avoid or limit:

• Grapefruit juice
• Cranberry juice
• Excess alcohol
• Smoking/tobacco use

Always inform your doctor or pharmacist about all prescription drugs, OTC medications, vitamins, and herbal supplements you use.

Pregnancy Warning

Warfarin may seriously harm an unborn baby and should generally not be used during pregnancy unless specifically directed by a specialist physician.

Serious Side Effects – Seek Medical Help Immediately

Contact your doctor immediately if you experience:

• Unusual bleeding or bruising
• Blood in urine or stool
• Black/tarry stools
• Vomiting blood
• Severe headache or dizziness
• Coughing up blood
• Purple or painful toes
• Skin discoloration or severe rash
• Severe stomach pain
• Yellowing of skin or eyes

Common Side Effects

Some patients may experience:

• Mild bruising
• Nosebleeds
• Joint or muscle pain
• Hair thinning
• Nausea or stomach discomfort

Proper Use

• Take once daily exactly as prescribed.
• Can be taken with or without food.
• If you miss a dose, take it as soon as remembered unless it is close to the next dose.
• Never double the dose.

Monitoring

Regular monitoring is essential:

• INR blood testing helps ensure proper clotting control.
• Your dose may change based on test results, diet, illness, or other medications.

Patient Disclaimer

This information is for educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Warfarin should only be used under the supervision of a qualified healthcare provider. Do not start, stop, or adjust your medication without consulting your doctor or pharmacist. Seek immediate medical attention if you experience signs of serious bleeding or allergic reactions.

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