 However, this free drug A is now more available for redistribution into the body tissues and/or for excretion.This means the total amount of drug in the system will decrease quite rapidly, keeping the free drug fraction (the concentration of free drug divided by the total drug concentration) constant and yielding almost no change in clinical effect .The effects of drugs displacing each other and changing the clinical effect (though important in some examples) is vastly overestimated usually and a common example incorrectly used to display the importance of this effect is the anticoagulant Warfarin.