Provided is a composition for maintaining platelet function that has as the active ingredient a compound represented by general formula (I) [in the formula: X indicates a phenylene group Y indicates a hydrogen atom or -(CH2)mR1 m indicates any integer from 0 to 4 R1 indicates -NR5COR2, -NR5SO2R2, or -NR3R4 R2 indicates a C1-C6 alkyl group, an aryl group, a C1-C6 alkoxy group, or the like R3 and R4 indicate a C1-C6 alkyl group or the like R5 indicates a hydrogen atom, a C1-C6 alkyl group, or the like and Z indicates a hydrogen atom or a C1-C6 alkyl group] or a salt thereof, or a solvate of the compound or the salt thereof.
