ampicillin vs sulfa drug

ampicillin

noun
  • A semisynthetic form of penicillin C₁₆H₁₉N₃O₄S that is effective against gram-negative and gram-positive bacteria and is used to treat infections of the urinary, respiratory, and intestinal tracts. 

sulfa drug

noun
  • Any of a group of antibiotic drugs structurally related to sulphonamide, tending to be bacteriostatic rather than bacteriocidal. 

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