Cocaine gets in the way of celebratory drink (8)
I believe the answer is:
champers
'celebratory drink' is the definition.
(I've seen this before)
'cocaine gets in the way of' is the wordplay.
'cocaine' becomes 'C' (drugs abbreviation).
'gets in the way of' becomes 'hampers' (I've seen this in another clue).
'c'+'hampers'='CHAMPERS'
(Other definitions for champers that I've seen before include "Kind of sparkling wine (slang)" , "Might they be extremely eager" , "Drink casually" , "something sparkling!" , "People who eat" .)