Point at which the anaesthetic gets you under (6)
I believe the answer is:
nether
'under' is the definition.
(synonyms)
'point at which the anaesthetic' is the wordplay.
'point' becomes 'n' (North).
'at which' is a charade indicator (letters next to each other).
'the anaesthetic' becomes 'ether' (ether is a kind of anaesthetic).
'n'+'ether'='NETHER'
'gets you' acts as a link.
(Other definitions for nether that I've seen before include "These garments are for the bottom half" , "North European country" , "Underground" , "These regions are hell, the underworld" , "inferior" .)