anesthetic vs relaxant

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. 

relaxant

noun
  • A drug or other agent that promotes relaxation. 

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