drug vs tranquilizer

drug

noun
  • A substance used to treat an illness, relieve a symptom, or modify a chemical process in the body for a specific purpose. 

  • Anything, such as a substance, emotion, or action, to which one is addicted. 

  • A psychoactive substance, especially one which is illegal and addictive, ingested for recreational use, such as cocaine. 

  • Any commodity that lies on hand, or is not salable; an article of slow sale, or in no demand. 

verb
  • To administer intoxicating drugs to, generally without the recipient's knowledge or consent. 

  • To add intoxicating drugs to with the intention of drugging someone. 

  • To prescribe or administer drugs or medicines. 

tranquilizer

noun
  • A drug used to reduce anxiety or tension. 

  • That which tranquillizes or soothes. 

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