Doctor rules out taking diazepam in the end for shaking (9)
I believe the answer is:
tremulous
'for shaking' is the definition.
(thesaurus)
'doctor rules out taking diazepam in the end' is the wordplay.
'doctor' indicates an anagram.
'taking' indicates putting letters inside.
'in the end' indicates one should take the final letters.
The final letter of 'diazepam' is 'm'.
'rules'+'out'='rulesout'
'rulesout' anagrammed gives 'treulous'.
'treulous' going around 'm' is 'TREMULOUS'.
(Other definitions for tremulous that I've seen before include "Timid; shaking" , "Timid; quivering" , "Shaking, quivering" , "Shaky" , "Slightly shaking" .)