pharmacology vs tranquilizer

pharmacology

noun
  • The properties and reactions of drugs especially with relation to their therapeutic value. 

  • The science of drugs including their origin, composition, pharmacokinetics, therapeutic use, and toxicology. 

tranquilizer

noun
  • A drug used to reduce anxiety or tension. 

  • That which tranquillizes or soothes. 

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