Don't Rush To The Newest Drug

In its September/October 2010 edition of  the American Society of Hematology's The Hematologist, Pete Lollar, M.D. reviews a report by Dutton, Wayman and Wei describing previously unknown actions by the anticoagulant warfarin (proprietary name - Coumadin)  used to combat abnormal venous and in-heart clotting which can produce strokes and pulmonary emboli with catastrophic results. Warfarin is also used as rat poison.

The report notably reports that vitamin K-dependent proteins involved in clotting involve vitamin K epoxide reductase ("VKOR") which is inhibited by warfarin. Humans are not the only life form which uses takes advantage of VKOR, since some bacteria including the one causing tuberculosis partially share VKOR activity.

There is a great deal of interest in new drugs which are being proposed to replace warfarin, a product which has been available since 1948 and, in addition to preventing strokes and pulmonary emboli, may be responsible for serious bleeding, particularly in women above age 80.  We are only beginning to understand the subtleties of the biologic action of warfarin.  When presented with the newcomer anticoagulants, how long will it take for us to understand how they work, and how many patients will experience serious unanticipated consequences of their adoption which we do not fully understand? Serious unanticipated consequences which rival the monitoring, cost savings and bleeding episodes now experienced with warfarin.