Leading lady takes drug before the end of the scene (7)
I believe the answer is:
heroine
'leading lady' is the definition.
(I've seen this in another clue)
'drug before the end of the scene' is the wordplay.
'drug' becomes 'heroin' (heroin is a kind of drug).
'before' is a charade indicator (letters next to each other).
'the end of the' says to take the final letters.
The final letter of 'scene' is 'e'.
'heroin'+'e'='HEROINE'
'takes' acts as a link.
(Other definitions for heroine that I've seen before include "Leading lady" , "Brave woman" , "Chief female character in a book" , "Woman of outstanding courage" , "The main good female character in a work of fiction" .)