Claimed to be working with drugs (7)
I believe the answer is:
medical
'with drugs' is the definition.
(with medical drugs)
'claimed to be working' is the wordplay.
'to be working' indicates an anagram.
'claimed' anagrammed gives 'MEDICAL'.
(Other definitions for medical that I've seen before include "Doctor's test" , "Check-up - declaim (anag)" , "Fitness examination" , "Declaim (anag) -- health check" , "Health check-up" .)