Replace Pilsner he's drunk (9)
I believe the answer is:
replenish
'replace' is the definition.
(I've seen this before)
'pilsner he's drunk' is the wordplay.
'drunk' indicates an anagram.
'pilsner'+'he'='pilsnerhe'
'pilsnerhe' with letters rearranged gives 'REPLENISH'.
(Other definitions for replenish that I've seen before include "Top up" , "Refill or make complete again" , "Replace" , "Fill again, renew a supply" , "Restock, refill" .)