Running through it, if first given a drink (8)
I believe the answer is:
aperitif
'drink' is the definition.
(aperitif is a kind of drink)
'running through it if first given a' is the wordplay.
'running through' indicates putting letters inside.
'first' becomes 'a' (first letter of the alphabet).
'given' says to put letters next to each other.
'a' becomes 'per' (eg 'one a day' means 'one per day').
'it'+'if'='itif'
'itif' put after 'a' is 'aitif'.
'aitif' going around 'per' is 'APERITIF'.
(Other definitions for aperitif that I've seen before include "Alcoholic drink to stimulate appetite" , "Pre-dinner drink" , "whistle-whetting drink" , "Pre-meal appetiser" , "Alcoholic beverage as an appetiser" .)