One replaced by queen in drug work (7)
I believe the answer is:
operate
'work' is the definition.
(I know that work can be written as operate)
'one replaced by queen in drug' is the wordplay.
I cannot quite see how this works, but
'one' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
'by' could be 'per' (I've seen this in another clue) and 'per' is present in the answer.
'drug' could be 'e' (E is another name for ecstasy) and 'e' is present in the answer.
The remaining letters 'at' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for operate that I've seen before include "effect" , "Act in a theatre" , "Work - perform surgery" , "Work, function" , "(Of machine) function" .)