Adenosine 5′-diphosphate (ADP) is an adenine nucleotide involved in energy storage and nucleic acid metabolism via its conversion into ATP by ATP synthases. ADP affects platelet activation through its interaction with ADP receptors P2Y1, P2Y12 and P2X1. Upon its conversion to adenosine by ecto-ADPases, platelet activation is inhibited via adenosine receptors. Adenosine 5′-diphosphate (ADP) is an adenine nucleotide involved in energy storage and nucleic acid metabolism via its conversion into ATP by ATP synthases. ADP affects platelet activation through its interaction with ADP receptors P2Y1, P2Y12 and P2X1. Upon its conversion to adenosine by ecto-ADPases, platelet activation is inhibited via adenosine receptors.