MDMA with powder taken up produces striking effect (5)
I believe the answer is:
eclat
'striking effect' is the definition.
(I've seen this before)
'mdma with powder taken up' is the wordplay.
'mdma' becomes 'E' (MDMA is ecstasy, ie 'E').
'with' means one lot of letters go next to another.
'powder' becomes 'talc' (talcing is a kind of powdering).
'taken up' says the letters should be written in reverse.
'talc' back-to-front is 'clat'.
'e'+'clat'='ECLAT'
'produces' is the link.
(Other definitions for eclat that I've seen before include "Brilliant success - striking effect" , "Loud applause" , "Ostentation" , "French renown" , "Ceremonial elegance and splendour" .)