Ordered wrong drug (4)
I believe the answer is:
bade
'ordered' is the definition.
(I've seen this before)
'wrong drug' is the wordplay.
'wrong' becomes 'bad' ().
'drug' becomes 'e' (e is another name for ecstasy).
'bad'+'e'='BADE'
(Other definitions for bade that I've seen before include "Ordered" , "Commanded with bead" , "Invited" .)