sulfamethoxazole

noun

sul·​fa·​meth·​ox·​a·​zole ˌsəl-fə-ˌme-ˈthäk-sə-ˌzōl 

: an antibacterial sulfonamide C₁₀H₁₁N₃O₃S used alone or in combination with trimethoprim (as in the treatment of urinary tract infections or acute otitis media)

Examples of sulfamethoxazole in a Sentence

Recent Examples on the Web

Another drug, trimethoprim-sulfamethoxazole, is an option for some older infants and adults. — Dr. Céline Gounder, CBS News, 19 Nov. 2025

Trimethoprim/sulfamethoxazole is the usual first-line antibiotic for cyclospora. — Bruce Y. Lee, Forbes.com, 29 July 2025

In reaching their conclusions, the researchers isolated nine different strains of bacteria that were shown to be resistant to the antibiotic sulfamethoxazole. — New Atlas, 9 July 2025

These infections don’t respond well to treatment from the common antibiotics ampicillin, azithromycin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole, per the report. — Rob Williams, EverydayHealth.com, 20 Apr. 2026

Word History

Etymology

sulfa + methyl + oxazole, a compound C₃H₃NO (from International Scientific Vocabulary ox- + azole)

First Known Use

1960, in the meaning defined above

Rhymes for sulfamethoxazole

• benzimidazole
• dipyridamole
• itraconazole
• ketoconazole
• metronidazole
• sulfathiazole
• thiabendazole
• acholi
• emboli
• sertoli
• unholy
• carbazole

Medical Definition

sulfamethoxazole

noun

sul·​fa·​meth·​ox·​a·​zole

variants or chiefly British sulphamethoxazole

-ˌmeth-ˈäk-sə-ˌzōl 

: an antibacterial sulfonamide C₁₀H₁₁N₃O₃S used alone (as in the treatment of urinary tract infections or prophylaxis against meningococcal meningitis) or in combination with trimethoprim (as in the treatment of Pneumocystis carinii pneumonia, shigellosis, acute otitis media, or urinary tract infections) see bactrim, septra