Warfarin bio-availability. A comparison of 4 products

The bio-availability of four warfarin tablet formulations--Marevan (Allen & Hanburys); Warfarin (Petersen); Coumadin (Boots) and Warfarin (Lennon)--administered as a single 10 mg oral dose, was compared in a single-blind cross-over study. Twelve healthy adult male volunteers participated in a clinical trial in which 95% confidence intervals for the true ratio (of the means) of each test product with respect to the reference product (Marevan) were calculated for maximum concentration and area under the plasma concentration time curve. The three test products differed by less than 20% from the reference product, suggesting that all four can be used interchangeably without risk of compromising safety and efficacy.