The present invention relates to a P2Y12receptor antagonist selected from the group consisting of 4-((R)-2-{[6-((S)-3-methoxy-pyrrolidin-1-yl)-2-phenyl-pyrimidine-4‑carbonyl]-amino}-3-phosphono-propionyl)-piperazine-1-carboxylic acid butyl ester, (1S,2S,3R,5S)-3-[7-[(1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino]-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]-5-(2-hydroxyethoxy)cyclopentane-1,2-diol, and (1S,2R,3S,4R)-4-[7-[(1R,2S)-2-(3,4-difluorophenyl)cyclopropylamino]-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]cyclopentane-1,2,3-triol, or a pharmaceutically acceptable salt thereof, for use as a medicament by subcutaneous or intradermal administration.本發明係關於選自由以下組成之群之P2Y12受體拮抗劑:4-((R)-2-{[6-((S)-3-甲氧基-吡咯啶-1-基)-2-苯基-嘧啶-4-羰基]-胺基}-3-膦醯基-丙醯基)-六氫吡嗪-1-甲酸丁基酯、(1S,2S,3R,5S)-3-[7-[(1R,2S)-2-(3,4-二氟苯基)環丙基胺基]-5-(丙硫基)-3H-[1,2,3]三唑并[4,5-d]嘧啶-3-基]-5-(2-羥基乙氧基)環戊烷-1,2-二醇及(1S,2R,3S,4R)-4-[7-[(1R,2S)-2-(3,4-二氟苯基)環丙基胺基]-5-(丙硫基)-3H-[1,2,3]三唑并[4,5-d]嘧啶-3-基]環戊烷-1,2,3-三醇或其醫藥上可接受之鹽,其用作藉由皮下或皮內投藥之藥劑。