opiate vs sleeping pill

opiate

noun
  • A drug, hormone or other substance derived from or related to opium. 

  • Something that dulls the senses and induces a false and unrealistic sense of contentment. 

adj
  • Soporific; inducing sleep or sedation. 

  • Relating to, resembling, or containing opium. 

  • Deadening; causing apathy or dullness. 

verb
  • To treat with an opiate drug. 

sleeping pill

noun
  • A pill or tablet having a soporific effect. 

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