Sulfamethizole is an oral antiobiotic, which was used against urinary tract infections under the name Thiosulfil. Sulfamethizole blocks bacterial growth by inhibiting folic acid synthesis via enzyme called dihydropteroate synthase. The drug is no longer marketed in the USA.

Sulfisomidine (INN), also known as sulphasomidine (BAN until 2003), is a sulfonamide antibacterial. It’s used in the treatment, control, prevention, and improvement of the following conditions and symptoms: Lower urinary tract infections; Meningococcal meningitis; Streptococcal pharyngitis; Gum infection; Bacillary dysentery.

Sulfisoxazole is a sulfonamide antibacterial antibiotic. The sulfonamides are synthetic bacteriostatic antibiotics with a wide spectrum against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfisoxazole acetyl in combination with erythromycin ethylsuccinate is used for treatment of ACUTE OTITIS MEDIA in children that is caused by susceptible strains of Haemophilus influenzae. Sulfisoxazole acetyl is a prodrug of sulfisoxazole. Acetyl group is added to make the drug poorly water soluble, and is hydrolyzed in vivo to the active drug. Sulfisoxazole and its acetylated metabolites are excreted primarily by the kidneys through glomerular filtration. Sulfisoxazole is a competitive inhibitor of the enzyme dihydropteroate synthetase. It inhibits bacterial synthesis of dihydrofolic acid by preventing the condensation of the pteridine with para-aminobenzoic acid (PABA), a substrate of the enzyme dihydropteroate synthetase. The inhibited reaction is necessary in these organisms for the synthesis of folic acid

Sulfamethazine is a sulfonamide used to treat a variety of bacterial diseases in animals. It inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA) for binding to dihydropteroate synthetase (dihydrofolate synthetase).

Sulfabenzamide is an antibacterial/antimicrobial. Often used in conjunction with sulfathiazole and sulfacetamide (trade name - Sultrin) as a topical, intravaginal antibacterial preparation against Haemophilus (Gardnerella) vaginalis bacteria. The mode of action of SULTRIN is not completely known. Indirect effects, such as lowering the vaginal pH, may be equally important mechanisms.

Sulfamerazine is a sulfonamide antibiotic, which acts by inhibiting folic acid synthesis in bacterias. The primary target of sulfamerazine is believed to be dihydropteroate synthetase. Sulfamerazine (in comination with Sulfadiazine and Sulfamethazine) was used in the US under different names, including the earliest brand of Neotrizine. Nowdays, the drugs containing sulfamerazine are no longer available for use in humans in the US, however, they may be prescribed for veterinary purposes.

Sulfanilamide is an anibiotic drug, which has been used for decades for the treatment of vulvovaginal candidiasis. The drug blocks folic acid synthesis in bacterias by inhibitin the enzyme dihydropteroate synthase.

SULFACLOZINE is a competitive antagonist of para-aminobenzoic acid (PABA), a precursor of folic acid, in protozoa and bacteria. It is indicated for treatment of coccidiosis in poultry due to infection with Eimeria species, fowl typhoid due to infection with Salmonella gallinarum and fowl cholera due to infection with Pasteurella multocida. Adverse reactions are liver damage, allergic reactions. In poultry undesirable effects, as inappetence, diarrhoea, growth depression, or haemorrhages after administration of sulfaclozine are rare. Prolong use may cause crystal urea.

Sulfaperine is a long-acting sulfonamide antibiotic.

Sulfadicramide, a sulfonamide with anti-anti-infective properties, it was applied as a 15% ointment for superficial infections of the eye.