diazepam vs hypnic

diazepam

noun

  • A tranquilizing muscle relaxant drug (trademark Valium) used chiefly to relieve anxiety. 

hypnic

noun

  • Any sleep-inducing drug. 

adj

  • That induces sleep. 

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