erythromycin vs sulfonamide

erythromycin

noun
  • A broad-spectrum macrolide antibiotic C₃₇H₆₇NO₁₃ produced by an actinomycete Saccharopolyspora erythraea (formerly Streptomyces erythreus) and similar in its effects to penicillin, administered orally or topically in the treatment of infections caused by Gram-positive bacteria. 

sulfonamide

noun
  • Any of a group of antibiotics; a sulfa drug 

  • Any amide of a sulfonic acid RS(=O)₂NR'₂ 

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