Effect of spiked drink with bit of temazepam in it (3,2)
I believe the answer is:
set up
'effect' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for set up that I've seen before include "The way something is arranged" , "Arrangement; trick" , "Established" , "Fool" , "Arrange; prepare; build" .)