tranquilizer vs xylazine

tranquilizer

noun
  • A drug used to reduce anxiety or tension. 

  • That which tranquillizes or soothes. 

xylazine

noun
  • A potent α₂-adrenergic agonist used for sedation, anesthesia, and analgesia in large mammals; it is also misused as an adulterant in street drugs. 

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