A simple model simulating the kinetics of drugs displacement kinetics is investigated. It is demonstrated that for highly bound, lowly cleared drugs, displacement interactions are transitory. Consequently, the kinetics of the interaction have to be considered as well as the in vitro interaction. It is possible to have a significant in vitro displacement interaction with no in vivo counterpart. Methods of moderating drug displacement by adjusting the rate and the timing of administration of the displacing agent are discussed.