In this review article, the currently employed or explored delivery concepts for local intravascular drug delivery with drug-eluting stents (DES) are discussed with a special emphasis on clinical evidence regarding the desired release profiles. Traditional concepts to control drug release from DES include diffusion through polymers, polymer degradation and erosion as well as dissolution of particulate drug. Published clinical studies do not always reveal fine mechanistic details. The long duration of release favored for DES and the short duration of release favored for drug-eluting balloons require further investigation in experimental studies and clinical trials.