[Problem] To provide an aqueous drug that contains the compound represented by formula (1) or a salt thereof and in which the precipitation and the chemical dissolution of the compound of formula (1) or of a salt thereof is inhibited.[Solution] An aqueous drug containing: the compound represented by formula (1) or a salt thereof and a magnesium compound. The aqueous drug has a pH of 5.8 - 6. 9. The concentration of the compound represented by formula (1) is 3 mg/mL or more.
