anesthetic vs hard drug

anesthetic

noun
  • A substance administered to reduce the perception of pain or to induce numbness for surgery and may render the recipient unconscious. 

adj
  • Insensate: unable to feel, or unconscious. 

  • Causing anesthesia; reducing pain sensitivity. 

hard drug

noun
  • An illegal, highly-addictive drug. 

How often have the words anesthetic and hard drug occurred in a corpus of books? (source: Google Ngram Viewer )