Drug distributed in Paris (7)
I believe the answer is:
aspirin
'drug' is the definition.
(aspirin is a kind of drug)
'distributed in paris' is the wordplay.
'distributed' indicates an anagram.
'in'+'paris'='inparis'
'inparis' is an anagram of 'ASPIRIN'.
(Other definitions for aspirin that I've seen before include "Synthetic analgesic" , "Pain-relief drug" , "Common drug in Paris" , "headache cure" , "Headache pill" .)