Cocaine high and drops of potent Armenian brew (5)
I believe the answer is:
cuppa
'brew' is the definition.
(I have seen 'Refreshing brew' mean 'cuppa' so perhaps 'brew' could also mean 'cuppa')
'cocaine high and drops of potent armenian' is the wordplay.
'cocaine' becomes 'C' (drugs abbreviation).
'high' becomes 'up' (associated in meaning).
'and' means one lot of letters go next to another.
'drops of' indicates taking the first letters (I've seen 'drop of' mean this).
The initial letters of 'potent armenian' is 'pa'.
'c'+'up'+'pa'='CUPPA'
(Other definitions for cuppa that I've seen before include "Drink of tea (informal)" , "Drink of tea (colloq.)" , "Refreshing brew" .)