Severity: High - Risk of internal bleeding

Those who take acetaminophen along with the widely used blood-thinning drug warfarin may face the risk of serious internal bleeding. People on warfarin who take acetaminophen for at least seven days in a row should be closely watched for bleeding.

Mitigation: Jan 5, 2014 by Dr. Adam Careful:

Asked patient to discontinue regular use of Tylenol and to consult with clinician if they need to resume to allow appropriate INR monitoring