Pharmacy Services

Warfarin Sodium(Coumadin®) - Patient Medication Guide and Black Box Warning

October 11, 2006

Pharmacists and prescribers are now required to give patients a Medication Guide for warfarin tablets (Coumadin®) whenever the drug is dispensed, so that patients are better informed about their medication.  Also, a black box warning was added to the product labeling to highlight important safety data about the risk of bleeding.  Warfarin is associated with a higher risk of bleeding during initiation of treatment and with high doses.  Patient-specific factors that increase the risk of bleeding include the following: aggressive anticoagulation (international normalized ratio [INR] > 4.0), age ≥ 65 years, unstable INRs, history of gastrointestinal bleeding, hypertension, cerebrovascular disease, severe heart disease, anemia, malignancy, trauma, renal insufficiency, concomitant medications and long duration of anticoagulation therapy.  Patients at higher risk of bleeding must have INRs monitored more frequently, understand how to prevent bleeding, and contact a physician when signs and symptoms of bleeding are present.  All manufacturers of warfarin (generic and brand) are required to provide Medication Guides with the product; however, Coumadin® is the only one currently available.

Additional information is available online at the following links:

Distribution of Medication Guides may be required with other medications that the FDA determines pose a serious and significant public health concern. This requirement applies primarily to medications dispensed in the outpatient setting (refer to Code of Federal Regulations 21CFR208.1). However, it may be appropriate to educate inpatients about the potential hazards of prescription medications, at the clinician's discretion. The complete list of drugs that require a Medication Guide as part of the FDA-regulated product labeling is available online at: http://www.fda.gov/cder/Offices/ODS/labeling.htm.

Updated
October 11, 2006; University of Utah, Drug Information Service. Copyright 2009, Drug Information Service, University of Utah, Salt Lake City, UT.