Generic Warfarin

Common use

This medication suppresses effects of vitamin K, which actively participates in clotting of the blood. It results in prevention of blood clot formation. Blood clots may form in different parts of body such as in vessels of extremities after periods of immobility, in vessels of lungs, around artificial heart valves causing embolism and shortness of breath, chest pain depending on the place where they block a vessel. Warfarin is used for treatment of patients with blood clots in the lower extremities, pulmonary embolism, atrial fibrillation, in certain orthopedic surgeries such as knee or hip replacements, myocardial infraction.



Dosage and direction

Never take a double dose of Warfarin. It maybe taken with or without food. Patients with liver or kidney dysfunction should take lower doses of the medication.



Precautions

Avoid eating cranberries or any cranberry herbal products, drinking alcohol and sports or activities that can result in bruising. If you need to do a lumbar puncture or any kind of surgery inform your doctor about taking Warfarin.



Contraindications

Acute bleeding, liver or kidney failure, acute arterial hypertension, pregnancy.



Possible side effect

Bleeding, necrosis of skin are among most dangerous ones. Black tarry stools, digestion disorders, nasal or gum bleeding, abundant and persisting menstrual discharge, unreasonable bruises, hair loss.





Drug interaction

Warfarin interacts with many drugs, and these interactions can be very dangerous. Mostly often such medications as aspirin, acetaminophen (Tylenol and others), alcohol, ibuprofen (Motrin), cimetidine (Tagamet), oxandrolone (Oxandrin), certain vitamins, and antibiotics should be taken into consideration while treatment with Warfarin is performed.



Missed dose

If you missed a dose take it as soon as you remember, but not if it is almost time of the next intake by your schedule. If it occurred do not take the missed dose and simply return to your regular schedule. Do not try to compensate a missed dose by taking an extra one. Never take a double dose of Warfarin.



Overdose

If you suspect that you took too much of the medication you may observe excessive bleeding from cuts or wounds, blood in the urine or stools, and heavy menstrual periods in women. Look for immediate medical help in such cases.



Storage

Store at room temperature in a dark dry place.



Disclaimer

We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis. Any specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim reliability of this information and mistakes it could contain. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.

Clinical Verification

Last Clinically Updated: August 15, 2026

Written By

Dr. Elena Vance, PharmD

Clinical Specialist in Neuropharmacology

Fact Checked By

Marcus Thorne, MS

Biomedical Data & FDA Label Verification

Medically Reviewed By

Dr. Arthur Campbell, MD

Board-Certified Psychiatrist (ABPN)