薬が効く
1
to have medicine be effective
運よく薬が効くとき１時過ぎに寝れるけど、薬を飲まないと４時ぐらいまで眠れない。
If I'm lucky enough for the medicine to work I can get to sleep after 1am but if I don't take it then I can't sleep until about 4am.
Other forms
薬がきく 【くすりがきく】 (search-only kanji form) · クスリが効く 【くすりがきく】 (search-only kanji form)