sulfa drug vs sulpha

sulfa drug

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

sulpha

noun
  • A sulphanilamide. 

adj
  • Of or containing sulphanilamide. 

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