Specific lots of Coumadin blood thinner tablets are being recalled by the manufacturer, Bristol-Myers Squibb, because the pills may have higher than expected potency. The recall involves one lot of 1,000-count bottles of coumadin (warfarin sodium) Crystalline 5 mg tablets. Higher than expected levels of the active ingredient may lead to an increased risk of severe bleeding which can be deadly. A lower than expected level of the active ingredient may increase the risk for blood clots which may lead to heart attack, stroke or even death.

Coumadin is a pill prescribed to prevent blood clots from forming or growing larger in the blood or blood vessels. It is prescribed for people with certain types of irregular heartbeat, people with prosthetic (replacement or mechanical) heart valves, and people who have suffered from a heart attack.

The recall includes only one lot, 9H49374A with an expiration date of September 30, 2012, which was distributed only in the United States. Patients who are taking 5 mg tablets should not interrupt their therapy but should seek advice from their pharmacist to see if they have tablets originating from the affected lot. If so, they should consult their physician for appropriate medical advice.

Health care professionals and patients are encouraged to report any serious side effects with this or any other mediation to the Food and Drug Administration MedWatch Adverse Event Reporting Program at www.FDA.gov/Medwatch.