PROBLEM TO BE SOLVED : To provide a medical drug for safely treating a patient who needs treatment by pemafibrate or a salt thereof, or a solvate thereof (hereinafter, also referred to as pemafibrate therapy). SOLUTION : A medical drug for treating a patient who needs pemafibrate therapy contains pemafibrate or a salt thereof or a solvate thereof as an active ingredient, in which the treatment includes a process of avoiding or stopping the combined use or reducing dosage of pemafibrate or a salt thereof or a solvate thereof in order to suppress rise of the concentration of pemafibrate in blood plasma in combined use with the medical drug containing clopidogrel or a salt thereof or a solvate thereof. SELECTED DRAWING : None COPYRIGHT : (C)2019, JPO&INPIT