Drug giving children inner power (5)
I believe the answer is:
speed
'drug' is the definition.
(speed is a kind of drug)
'children inner power' is the wordplay.
'children' becomes 'seed' (I've seen this before).
'inner' is an insertion indicator.
'power' becomes 'p'.
'seed' enclosing 'p' is 'SPEED'.
'giving' acts as a link.
(Other definitions for speed that I've seen before include "Swiftness" , "Move quickly (and illegally?)" , "Pace or tempo" , "Race" , "Alacrity" .)