Medication range mostly treating cuts (7)
I believe the answer is:
linctus
'medication' is the definition.
(thesaurus)
'range mostly treating cuts' is the wordplay.
'range' becomes 'line' (I've seen this in other clues).
'mostly' means to remove the last letter (most but not all of the word).
'treating' indicates anagramming the letters.
'line' with its final letter taken off is 'lin'.
'cuts' is an anagram of 'ctus'.
'lin'+'ctus'='LINCTUS'
(Other definitions for linctus that I've seen before include "Cough-medicine" , "Syrup that may see a cough off" , "Cough medicine" , "Soothing drink" , "The prescription" .)