Effects of Enteral Formulas and Their Food Protein and Dietary Fiber Components on Postprandial Plasma Warfarin Concentration in Rats

The purpose of this study was to clarify the effects of enteral formulas and their food protein and dietary fiber components on the pharmacokinetics of warfarin in rats. Blood samples were collected from 0 to 30 h after the oral administration of 0.5 (milk protein or casein), or dietary fiber (indigestible dextrin or carrageenan). Plasma warfarin concentration was determined by liquid chromatography-tandem mass spectrometry. Plasma warfarin concentration was lower at the initial phase after co-administration of F2 Light & REG;, milk protein, or casein compared with the control group, which might have been caused by the suppression of the gastrointestinal absorption of warfarin in accordance with the binding to food protein. Plasma warfarin concentration was significantly higher after co-administration of Mei Flow & REG;, indigestible dextrin, or carrageenan compared with the control group. This is the first study to find that the plasma concentration of warfarin increases when warfarin is co-administered with enteral formula Mei Flow & REG; or their dietary fiber components such as indigestible dextrin or carrageenan. Therefore, close attention should be paid to decreases or increases in the plasma warfarin concentration when warfarin is used with enteral formula.