sulfa drug

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of a group of synthetic organic compounds, derived chiefly from sulfanilamide, chemically similar to PABA and capable of inhibiting bacterial growth and activity by interfering with the metabolic processes in bacteria that require PABA. Also called sulfonamide.

Wiktionary

1. n. Antibiotic drugs related to sulphonamide in chemical structure, tending to be bacteriostatic rather than bacteriocidal.

WordNet 3.0

1. n. antibacterial consisting of any of several synthetic organic compounds capable of inhibiting the growth of bacteria that require PABA