sulfa vs sulfonamide

sulfa

noun

  • A sulfonamide or sulfanilamide. 

adj

  • Of or containing sulfonamide or sulfanilamide. 

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 sulfa and sulfonamide occurred in a corpus of books? (source: Google Ngram Viewer )