Source of medicine rapid to limit damage (8)
I believe the answer is:
pharmacy
'source of medicine' is the definition.
'pharmacy' can be an answer for 'medicine' (pharmacy is a kind of medicine). I am not sure about the 'source of' bit.
'rapid to limit damage' is the wordplay.
'rapid' becomes 'pacy' (I can't justify this - if you can you should believe this answer much more).
'to limit' indicates putting letters inside (outside letters limit or restrain others).
'damage' becomes 'harm' (synonyms).
'pacy' placed around 'harm' is 'PHARMACY'.
Can you help me to learn more?
(Other definitions for pharmacy that I've seen before include "Dispensary" , "A chemist's shop where prescriptions are dispensed" , "Place where drugs are prepared or sold" , "Where drugs are dispensed" , "Where chemist works" .)