Pair from Australia caught importing advanced drug (6)
I believe the answer is:
prozac
'drug' is the definition.
(I've seen this before)
'pair from australia caught importing advanced' is the wordplay.
'pair from' becomes 'prc' (I am not sure about this - if you are sure you should believe this answer much more).
'australia' becomes 'oz' (informal name for Australia).
'caught' is an insertion indicator.
'importing' indicates putting letters inside.
'advanced' becomes 'a' (abbreviation).
'prc' placed around 'oz' is 'prozc'.
'prozc' enclosing 'a' is 'PROZAC'.
Can you help me to learn more?
(Other definitions for prozac that I've seen before include "Anti-depressant trade mark" , "Common antidepressant drug" , "Controversial antidepressant" , "Upper" , "medication" .)