Warfarin is an anticoagulant or blood thinner that reduces the likelihood of blood clots, stroke, and heart attack. It works by decreasing the amount of specific clotting proteins in the blood, allowing smoother blood flow through the body.

Dosage and Uses

Warfarin is commonly available in tablet form, with doses ranging from 1 to 10 mg. It is used to treat conditions such as deep vein thrombosis, thromboembolism, stroke and heart attack, rheumatic heart disease, systolic dysfunction, antiphospholipid syndrome, and post-heart valve replacement.

Drug Interactions

Warfarin should not be used with drugs like apixaban, defibrotide, or mifepristone. It has severe interactions with medications such as abciximab, allopurinol, amiodarone, and others. Consult a doctor for alternatives if these interactions pose a risk.

Side Effects

Common side effects of Warfarin include cholesterol embolism syndrome, intraocular bleeding, abdominal pain, alopecia, rash, pruritus, taste disturbances, tissue necrosis, headache, fatigue, dizziness, hematuria, anemia, hepatitis, respiratory bleeding, hypersensitivity, blood dyscrasias, fever, "purple toe syndrome," increased fracture risk, calciphylaxis, acute kidney injury, and ischemia in limbs.

Contraindications

• During pregnancy (except for mothers with mechanical heart valves)
• Post-surgery, especially major or eye surgeries
• In cases of miscarriage risk, preeclampsia, or eclampsia
• In patients prone to dementia, alcohol addiction, or psychosis without medical supervision
• In spinal injuries or severe bleeding conditions
• During spinal or general anesthesia
• Severe hypertension

Warnings

• Warfarin can cause severe or fatal bleeding, especially at the start of treatment or at higher doses.
• Lower doses may be required for the elderly, malnourished, and those with liver conditions.
• Genetic testing to determine the optimal dose is recommended.
• Healthcare providers must be informed about Warfarin use.
• Patients with acute infections should use caution, as antibiotics and fever can alter Warfarin's effects.
• Long-term vitamin K deficiency should be monitored closely when using Warfarin.
• Thyroid disorders may enhance the body's response to Warfarin.
• Liver dysfunction can reduce clotting factors, increasing sensitivity to Warfarin.
• Use caution during breastfeeding and consult a doctor.
• Maintain adequate dietary vitamin K levels, as excess intake can reduce Warfarin's efficacy.

Pregnancy and Breastfeeding

Warfarin use during pregnancy can lead to severe congenital anomalies, heavy bleeding, and spontaneous miscarriage. Effective contraception is recommended during treatment and for at least one month after the last dose.

Although Warfarin does not appear to pass into breast milk, it may cause serious side effects, including bleeding in the infant. Consult a doctor to evaluate the risks and benefits before using Warfarin during breastfeeding.