Drug high involved bonfire outside (9)
I believe the answer is:
ibuprofen
'drug' is the definition.
(ibuprofen is a kind of drug)
'high involved bonfire outside' is the wordplay.
I cannot really see how this works, but
'high' could be 'up' (associated in meaning) and 'up' is present in the answer.
an anagram of 'bonfire' is 'ibrofen' which is located in the left over letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ibuprofen that I've seen before include "anaesthetic" , "Painkiller" , "Drug" , "Anti-inflammatory medicine" .)