Cephradine is a semisynthetic cephalosporin antibiotic. Cephradine is active against the following organisms in vitro: Group A beta-hemolytic streptococci; Staphylococci, including coagulase-positive, coagulase-negative, and penicillinase-producing strains; Streptococcus pneumoniae (formerly Diplococcus pneumoniae); Escherichia coli; Proteus mirabilis; Klebsiella species; Hemophilus influenza. It works by stopping the growth of bacteria. It is used to treat a wide variety of bacterial infections (e.g., skin, ear, respiratory and urinary tract infections). Pseudomembranous colitis has been reported in patients receiving cephradine both orally and intravenously. Diarrhea generally starts 1 to 16 days after starting cephradine therapy. Gastrointestinal side effects have included nausea, vomiting. Hypersensitivity reactions have included rash, urticaria, pruritus, and joint pain. Bacteriostats may interfere with the bactericidal action of cephalosporins in acute infection; other agents, e.g., aminoglycosides, colistin, polymyxins, vancomycin, may increase the possibility of nephrotoxicity.

Carfecillin is a phenyl ester of the side-chain carboxyl group of carbenicillin, beta-lactam antibiotic, acting as a prodrug. Upon oral administration, is broken down in the intestinal mucosa to the active antibacterial. It is used for urinary tract infections.

Cloxacillin is a derivative of penicillin for the treatment of broad spectrum of bacterial infections. The drug exerts its action by inhiiting bacterial beta-lactamase (penicillin-binding proteins).

Nalidixic acid is a quinolone antibacterial indicated for the treatment of urinary tract infections. Nalidixic acid has marked antibacterial activity against gram-negative bacteria including Enterobacter species, Escherichia coli, Morganella Morganii; Proteus Mirabilis, Proteus vulgaris, and Providencia rettgeri. Pseudomonas species are generally resistant to the drug. It is suggested that nalidixic acid acts by inhibiting bacterial DNA gyrase.

Sulfinpyrazone was approved by the U.S. Food and Drug Administration (FDA) on May 13, 1959. It was developed and marketed as Anturane® by Novartis. Sulfinpyrazone is an oral uricosuric agent (pyrazolone derivative) used to treat chronic or intermittent gouty arthritis. Sulfinpyrazone competitively inhibits the reabsorption of uric acid at the proximal convoluted tubule, thereby facilitating urinary excretion of uric acid and decreasing plasma urate concentrations. This is likely done through inhibition of the urate anion transporter (hURAT1) as well as the human organic anion transporter 4 (hOAT4). Sulfinpyrazone is not intended for the treatment of acute attacks because it lacks therapeutically useful analgesic and anti-inflammatory effects. Sulfinpyrazone and its sulfide metabolite possess COX inhibitory effects. Sulfinpyrazone has also been shown to be a UDP-glucuronsyltransferase inhibitor and a very potent CYP2C9 inhibitor. Sulfinpyrazone is also known to be a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor as well as an inhibitor of several multridrug resistance proteins (MRPs). Branded and generic forms of sulfinpyrazone have been discontinued in the US.

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.

Chloramphenicol is a broad-spectrum antibiotic that was first isolated from Streptomyces venezuelae in 1947. The drug was subsequently chemically synthesized. It has both a bacteriostatic and bactericidal effect; in the usual therapeutic concentrations it is bacteriostatic. Chloramphenicol is used for the treatment of serious gram-negative, gram-positive, and anaerobic infections. It is especially useful in the treatment of meningitis, typhoid fever, and cystic fibrosis. It should be reserved for infections for which other drugs are ineffective or contraindicated. Chloramphenicol, a small inhibitor of bacterial protein synthesis, is active against a variety of bacteria and readily enters the CSF. It has been used extensively in the last decades for the treatment of bacterial meningitis. In industrialized countries, chloramphenicol is restricted mostly to topical uses because of the risk of induction of aplastic anemia. However, it remains a valuable reserve antibiotic for patients with allergy to β-lactam antibiotics or with CNS infections caused by multiresistant pathogens.

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

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.

Flucloxacillin is an isoxazolyl penicillin of the β-lactam group of antibiotics, which exerts a bactericidal effect upon many Gram-positive organisms including β-lactamase-producing staphylococci and streptococci. While no longer used in the United States, Flucloxacillin is supplied under a variety of trade names in other countries, including Floxapen, Flopen, Staphylex. Floxapen is indicated for the treatment of infections due to sensitive Gram-positive organisms, including β-lactamase-producing staphylococci and streptococci. Typical indications including, skin and soft tissue infections; respiratory tract infections; other infections caused by floxapen-sensitive organisms, like example, osteomyelitis, urinary tract infection, septicaemia, endocarditis. Floxapen is also indicated for use as a prophylactic agent during major surgical procedures when appropriate; for example cardiothoracic and orthopaedic surgery. Flucloxacillin, by its action on the synthesis of the bacterial wall, exerts a bactericidal effect on streptococci except those of group D (Enterococcus faecalis) staphylococci. It is not active against methicillin-resistant staphylococci. There is evidence that the risk of flucloxacillin induced liver injury is increased in subjects carrying the HLA-B*5701 allele. Despite this strong association, only 1 in 500-1000 carriers will develop liver injury. Consequently, the positive predictive value of testing the HLA-B*5701 allele for liver injury is very low (0.12%) and routine screening for this allele is not recommended. Flucloxacillin diffuses well into most tissue. Specifically, active concentrations of flucloxacillin have been recovered in bones: 11.6 mg/L (compact bone) and 15.6 mg/L (spongy bone), with a mean serum level of 8.9 mg/L. Flucloxacillin diffuses in only small proportion into the cerebrospinal fluid of subjects whose meninges are not inflamed. It is also excreted in small quantities in mother's milk. In normal subjects approximately 10% of the flucloxacillin administered is metabolised to penicilloic acid. The elimination half-life of flucloxacillin is in the order of 53 minutes.