Nevertheless, doctors wrote 21 million prescriptions for the anti-coagulant Coumadin (generically known as warfarin), a drug growing 5% a year.

FORBES: The Plot Thickens

For 60 years, doctors have had only one pill to prevent clotting: warfarin, a drug originally derived from rat poison and sold under the brand name Coumadin by Bristol-Myers Squibb (nyse: BMY - news - people ).

FORBES: Replacing Coumadin