Go mad for an alcoholic concoction (4)
I believe the answer is:
flip
This clue is a double definition.
'go mad' is the first definition.
(to flip is to become very angry suddenly)
'an alcoholic concoction' is the second definition.
(type of alcoholic drink)
'for' acts as a link.
(Other definitions for flip that I've seen before include "Toss - flick - turn over" , "See red" , "Toss a pancake" , "Flick or toss, say coin" , "Toss e.g. a coin" .)