--- title: "TMP-SMX: What it is and why it's important" date: 2023-11-04T04:45:00-07:00 author: Julie Dueck canonical_url: "https://marlerclark.com/news_events/tmp-smx-what-they-are-and-why-theyre-important" section: News --- [All News](/news_events) / [Case News](https://marlerclark.com/news_events/case-news) / # TMP-SMX: What it is and why it's important Trimethoprim-sulfamethoxazole (TMP-SMX), also known as co-trimoxazole, is a combination of two antimicrobial agents that act synergistically against a wide variety of bacteria. It is commonly used to treat urinary tract infections, middle ear infections, bronchitis, traveler’s diarrhea, and shigellosis (bacillary dysentery). TMP-SMX is also used to prevent or treat Pneumocystis jiroveci pneumonia or Pneumocystis carinii pneumonia. The two components, TMP and SMX, work sequentially to inhibit enzyme systems involved in the bacterial synthesis of tetrahydrofolic acid (THF). TMP binds to bacterial dihydrofolate reductase (in preference to human dihydrofolate reductase), preventing the formation of THF. SMX is a structural analog of para-aminobenzoic acid (PABA) and competes with PABA to inhibit the synthesis of dihydrofolic acid, an intermediate step in the formation of THF. TMP-SMX is an important drug in the treatment of various bacterial infections. However, it is important to note that antibiotics should only be used when necessary and as prescribed by a healthcare professional. Overuse of antibiotics can lead to antibiotic resistance, which can make it difficult to treat bacterial infections. Therefore, it is important to use antibiotics judiciously and only when necessary. ### Lawsuit updates about foodborne illnesses [Reactive Arthritis Lawsuit Updates](/news_events/case-news?illness=reactive-arthritis&year=all) [E. coli Lawsuit Updates](/news_events/case-news?illness=e-coli&year=all) [Guillain-Barre Syndrome Lawsuit Updates](/news_events/case-news?illness=guillain-barre-syndrome&year=all) [Salmonella Lawsuit Updates](/news_events/case-news?illness=salmonella&year=all) [Hemolytic Uremic Syndrome Lawsuit Updates](/news_events/case-news?illness=hemolytic-uremic-syndrome&year=all) [Listeria Lawsuit Updates](/news_events/case-news?illness=listeria&year=all) [Irritable Bowel Syndrome Lawsuit Updates](/news_events/case-news?illness=irritable-bowel-syndrome&year=all) [Hepatitis A Lawsuit Updates](/news_events/case-news?illness=hepatitis-a&year=all) [Norovirus Lawsuit Updates](/news_events/case-news?illness=norovirus&year=all) [Botulism Lawsuit Updates](/news_events/case-news?illness=botulism&year=all) [Campylobacter Lawsuit Updates](/news_events/case-news?illness=campylobacter&year=all) [Shigella Lawsuit Updates](/news_events/case-news?illness=shigella&year=all) [Cyclospora Lawsuit Updates](/news_events/case-news?illness=cyclospora&year=all) ### Lawsuits updates by year [Foodborne Illness Lawsuits in 1998](https://marlerclark.com/news_events/case-news?illness=all&year=1998) [Foodborne Illness Lawsuits in 1999](https://marlerclark.com/news_events/case-news?illness=all&year=1999) [Foodborne Illness Lawsuits in 2000](https://marlerclark.com/news_events/case-news?illness=all&year=2000) [Foodborne Illness Lawsuits in 2001](https://marlerclark.com/news_events/case-news?illness=all&year=2001) [Foodborne Illness Lawsuits in 2002](https://marlerclark.com/news_events/case-news?illness=all&year=2002) [Foodborne Illness Lawsuits in 2003](https://marlerclark.com/news_events/case-news?illness=all&year=2003) [Foodborne Illness Lawsuits in 2004](https://marlerclark.com/news_events/case-news?illness=all&year=2004) [Foodborne Illness Lawsuits in 2005](https://marlerclark.com/news_events/case-news?illness=all&year=2005) [Foodborne Illness Lawsuits in 2006](https://marlerclark.com/news_events/case-news?illness=all&year=2006) [Foodborne Illness Lawsuits in 2007](https://marlerclark.com/news_events/case-news?illness=all&year=2007) [Foodborne Illness Lawsuits in 2008](https://marlerclark.com/news_events/case-news?illness=all&year=2008) [Foodborne Illness Lawsuits in 2009](https://marlerclark.com/news_events/case-news?illness=all&year=2009) [Foodborne Illness Lawsuits in 2010](https://marlerclark.com/news_events/case-news?illness=all&year=2010) [Foodborne Illness Lawsuits in 2011](https://marlerclark.com/news_events/case-news?illness=all&year=2011) [Foodborne Illness Lawsuits in 2012](https://marlerclark.com/news_events/case-news?illness=all&year=2012) [Foodborne Illness Lawsuits in 2013](https://marlerclark.com/news_events/case-news?illness=all&year=2013) [Foodborne Illness Lawsuits in 2014](https://marlerclark.com/news_events/case-news?illness=all&year=2014) [Foodborne Illness Lawsuits in 2015](https://marlerclark.com/news_events/case-news?illness=all&year=2015) [Foodborne Illness Lawsuits in 2016](https://marlerclark.com/news_events/case-news?illness=all&year=2016) [Foodborne Illness Lawsuits in 2017](https://marlerclark.com/news_events/case-news?illness=all&year=2017) [Foodborne Illness Lawsuits in 2018](https://marlerclark.com/news_events/case-news?illness=all&year=2018) [Foodborne Illness Lawsuits in 2019](https://marlerclark.com/news_events/case-news?illness=all&year=2019) [Foodborne Illness Lawsuits in 2020](https://marlerclark.com/news_events/case-news?illness=all&year=2020) [Foodborne Illness Lawsuits in 2021](https://marlerclark.com/news_events/case-news?illness=all&year=2021) [Foodborne Illness Lawsuits in 2022](https://marlerclark.com/news_events/case-news?illness=all&year=2022) [Foodborne Illness Lawsuits in 2023](https://marlerclark.com/news_events/case-news?illness=all&year=2023) [Foodborne Illness Lawsuits in 2024](https://marlerclark.com/news_events/case-news?illness=all&year=2024) [Foodborne Illness Lawsuits in 2025](https://marlerclark.com/news_events/case-news?illness=all&year=2025) [Foodborne Illness Lawsuits in 2026](https://marlerclark.com/news_events/case-news?illness=all&year=2026) ##### Get Help #### Affected by an outbreak or recall? 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