Consumes American drink round back of roadhouse (4,2)
I believe the answer is:
uses up
'consumes' is the definition.
('use up' can be a synonym of 'consume')
'american drink round back of roadhouse' is the wordplay.
'american' becomes 'US' (abbreviation for United States).
'drink' becomes 'sup' (to sup is to drink).
'round' is an insertion indicator.
'back of' indicates one should take the final letters.
The final letter of 'roadhouse' is 'e'.
'us'+'sup'='ussup'
'ussup' enclosing 'e' is 'USES UP'.
(Other definitions for uses up that I've seen before include "Consumes" , "drains" , "'Depletes (4,2)'" , "Exhausts" .)