TV doctor with a call for restraint (4)
I believe the answer is:
whoa
'call for restraint' is the definition.
'tv doctor with a' is the wordplay.
'tv doctor' becomes 'who' (I've seen this in other clues).
'with' says to put letters next to each other.
'who'+'a'='WHOA'
(Other definitions for whoa that I've seen before include "Hold your horses!" , "Command to horse to stop or stand still" , "Said to stop a horse" , "Instruction to a horse to stop" , "Command for horse to slow or stop" .)