Effects of the number of drugs used on the prevalence of adverse drug reactions in children oleh Mayuko Sugioka, Tomoya Tachi, Takashi Mizui, Aisa Koyama, Azusa Murayama, Hayato Katsuno, Takuya Matsuyama, Satoshi Aoyama, Tomohiro Osawa, Yoshihiro Noguchi, Masahiro Yasuda, Chitoshi Goto, Hitomi Teramachi