Sulfamethoxazole

Sulfamethoxazole
Clinical data
Trade names	Gantanol
AHFS/Drugs.com	Micromedex Detailed Consumer Information
Pregnancy; category	AU: C;
Routes of; administration	Oral, IV
ATC code	J01EC01 (WHO) QJ01EQ11 (WHO);
Legal status
Legal status	AU: S4 (Prescription only); CA: ℞-only; UK: POM (Prescription only); US: ℞-only;
Pharmacokinetic data
Protein binding	70%
Metabolism	Hepatic acetylation and glucuronidation
Elimination half-life	10 hours
Excretion	Renal
Identifiers
	IUPAC name 4-Amino-N-(5-methylisoxazol-3-yl)-benzenesulfonamide;
CAS Number	723-46-6 ;
PubChem CID	5329;
DrugBank	DB01015 ;
ChemSpider	5138 ;
UNII	JE42381TNV;
KEGG	D00447 ;
ChEBI	CHEBI:9332 ;
ChEMBL	ChEMBL443 ;
NIAID ChemDB	006897;
CompTox Dashboard (EPA)	DTXSID8026064 ;
ECHA InfoCard	100.010.877
Chemical and physical data
Formula	C10H11N3O3S
Molar mass	253.28 g·mol−1
3D model (JSmol)	Interactive image;
Melting point	169 °C (336 °F)
	SMILES Nc1ccc(cc1)S(=O)(=O)Nc2cc(C)on2;
	InChI InChI=1S/C10H11N3O3S/c1-7-6-10(12-16-7)13-17(14,15)9-4-2-8(11)3-5-9/h2-6H,11H2,1H3,(H,12,13) ; Key:JLKIGFTWXXRPMT-UHFFFAOYSA-N ;
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Sulfamethoxazole (SMZ or SMX) is an antibiotic. It is used for bacterial infections such as urinary tract infections, bronchitis, and prostatitis and is effective against both gram negative and positive bacteria such as Escherichia coli and Listeria monocytogenes.

Common side effects include nausea, vomiting, loss of appetite, and skin rashes. It is a sulfonamide and bacteriostatic. It resembles a component of folic acid. It prevents folic acid synthesis in the bacteria that must synthesize their own folic acid. Mammalian cells, and some bacteria, do not synthesize but require preformed folic acid (vitamin B9); they are therefore insensitive to sulfamethoxazole.

It was introduced to the United States in 1961. It is now mostly used in combination with trimethoprim (abbreviated SMX-TMP). The SMX-TMP combination is on the WHO Model List of Essential medicines as a first-choice treatment for urinary tract infections. Other names include: sulfamethalazole and sulfisomezole.