Drink up? Not when in charge (5)
I believe the answer is:
tonic
'drink' is the definition.
(I know that tonic is a type of soft drink)
'up? not when in charge' is the wordplay.
I cannot really understand how this works, but
an anagram of 'not' is 'ton' which is within the answer.
'in charge' could be 'ic' (abbreviation for 'in charge') and 'ic' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tonic that I've seen before include "Invigorating liquid" , "It goes with gin" , "A pick-me-up drink, nice with gin" , "Quinine drink; keynote" , "Accompaniment to gin?" .)