An object of the present invention is to provide a medicament and method which is useful for prevention and / or therapy of
arterial wall injury. According to the present invention, there is provided a method for prevention and / or therapy of
arterial wall injury which comprises a step of administering the
pyrazolone derivative represented by the following formula (I) or the physiologically acceptable salt thereof, or the
hydrate or solvate thereof in a preventively or therapeutically effective amount to mammals including humans:wherein R1 represents a
hydrogen atom, an
aryl group, an
alkyl group, or an alkoxycarbonylalkyl group; R2 represents a
hydrogen atom, an aryloxy group, an arylmercapto group, an
alkyl group or a hydroxyalkyl group; or R1 and R2 are combined with each other to represent an alkylene group; and R3 represents a
hydrogen atom, an
alkyl group, a cycloalkyl group, a hydroxyalkyl group, a
benzyl group, a naphthyl group, a
phenyl group, or a
phenyl group substituted with 1 to 3 substituents selected from the group consisting of an alkyl group, an
alkoxy group, a hydroxyalkyl group, an alkoxycarbonyl group, an alkylmercapto group, an alkylamino group, a dialkylamino group, a
halogen atom, a
trifluoromethyl group, a carboxyl group, a cyano group, a hydroxyl group, a nitro group, an amino group and an
acetamide group.