↑ bleeding risk with anise, arnica, chamomile, clove, dong quai, fenugreek, feverfew, garlic, ginger, ginkgo, Panax ginseng, licorice , and others.

Many other drugs may affect the activity of warfarin.

Barbiturates, carbamazepine, rifampin, and hormonal contraceptives containing estrogen may ↓ the anticoagulant response to warfarin.

Acute alcohol ingestion may ↑ action of warfarin.Chronic alcohol ingestion may ↓ action of warfarin if chronic alcohol abuse results in significant liver damage, action of warfarin may be ↑ due to ↓ production of clotting factor.Chronic use of acetaminophen may ↑ the risk of bleeding.Androgens, capecitabine, cefotetan, chloramphenicol, clopidogrel, disulfiram, fluconazole, fluoroquinolones, itraconazole, metronidazole (including vaginal use), thrombolytics, eptifibatide, tirofiban, sulfonamides, quinidine, quinine, NSAIDs, valproates, and aspirin may ↑ the response to warfarin and ↑ the risk of bleeding.If already using warfarin, it may be reasonable to continue treatment, especially if INR is well controlled (i.e., >70% time in therapeutic range) and no adverse effects.Īdverse Reactions/Side Effects Adverse Reactions/Side Effects Avoid starting as initial therapy for treatment of nonvalvular atrial fibrillation or venous thromboembolism unless alternative options (DOACs) are contraindicated or there are significant barriers to their use. ↑ risk of major bleeding when compared to direct acting oral anticoagulants (DOACs) in older adults.

Pedi: Has been used safely in children, but may require more frequent PT/INR assessments.Asian patients or those who carry the CYP2C9*2 allele and/or the CYP2C9*3 allele, or with the VKORC1 AA genotype (↑ risk of bleeding with standard dosing lower initial doses should be considered).History of ulcer, liver disease, or acute kidney injury.Recent brain, eye, or spinal cord injury or surgery.

Vitamin k antidote warfarin