The present invention relates to a medicament for treating a disease in which Nav1.7 is involved, specifically diseases such as neuropathic pain, nociceptive pain, inflammatory pain, small-fiber neuropathy, erythromelalgia, paroxysmal extreme pain disorder, dysuria, and multiple sclerosis, comprising a compound of formula (I):or a pharmaceutically acceptable salt thereof wherein R1a, R1b, R1c, and R1dis hydrogen, halogen, cyano, C1-4alkyl, C1-4alkoxy, or the like, provided at least one of R1a, R1b, R1c, and R1dis C6-10aryl, C6-10aryloxy, or the like, R2and R3are hydrogen, C1-6alkyl, C3-10cycloalkyl, or the like, R4is hydrogen, C1-6alkyl, C3-7cycloalkyl, or the like, m is 1, 2, or 3, L is CR7R8, and R7and R8are hydrogen, hydroxide, C1-4alkyl, C1-4alkoxy, or the like.本發明提供一種針對與Nav1.7相關之疾病、具體為神經病變性疼痛、傷害感受性疼痛、炎症性疼痛、小纖維神經病變、肢端紅痛症、陣發性劇痛症、排尿障礙或多發性硬化症等疾病之治療藥。 本發明提供一種化合物或其製藥學上所容許之鹽，該化合物係由式(I)所表示：[式中，R1a、R1b、R1c及R1d表示氫、鹵素、氰基、C1-4烷基、C1-4烷氧基等，其中，R1a、R1b、R1c或R1d之至少一者表示C6-10芳基、C6-10芳氧基等，R2及R3表示氫、C1-6烷基、C3-10環烷基等，R4表示氫、C1-6烷基、C3-7環烷基等，m表示1、2或3，L表示CR7R8，R7及R8表示氫、羥基、C1-4烷基、C1-4烷氧基等]。
