Question

an·es·thet·ic
  (US)   ( or Brit   an·aes·thet·ic) /ˌænəsˈθɛtık/  noun  ,  pl   -ics [  count  ]
   medical   : a drug that causes a person to lose feeling and to feel no pain in part or all of the body
   The doctor gave him the stitches without an anesthetic.
   The surgery required a general anesthetic. [=a drug that makes a person unconscious and unable to feel pain]
   a local anesthetic [=a drug that makes a part of the body unable to feel pain]
  anesthetic  (US)   ( or Brit   anaesthetic)  adj  
   the anesthetic properties of a drug