Ask the doctor: Warfarin interactions
Some drugs raise or lower the effects of warfarin itself. For example, some antibiotics cause warfarin to have stronger effects—thus, a person getting a short course of antibiotics for a sinus infection may see his or her INR (a measure of blood coagulation) go up, meaning blood takes more time to clot. Under those circumstances, a person might experience bleeding gums, bloody stools, or other bleeding problems. Other drugs and supplements diminish warfarin's anti-clotting activity, which increases the odds of developing a potentially harmful blood clot. And people take warfarin because they are already at risk for forming just such clots.
To continue reading this article, you must log in.
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
- Research health conditions
- Check your symptoms
- Prepare for a doctor's visit or test
- Find the best treatments and procedures for you
- Explore options for better nutrition and exercise
I'd like to receive access to Harvard Health Online for only $4.99 a month.
Sign Me UpAlready a member? Login ».
Disclaimer:
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
