Cefaclor is a semisynthetic cephalosporin antibiotic for oral administration. As with other cephalosporins, the bactericidal action of Cefaclor results from inhibition of cell-wall synthesis. Cefaclor is indicated in the treatment of the following infections when caused by susceptible strains of the designated microorganisms: Otitis media caused by Streptococcus pneumoniae, Haemophilus influenzae, staphylococci, and Streptococcus pyogenes; Lower respiratory tract infections, including pneumonia, caused by Streptococcus pneumoniae, Haemophilus influenzae, and Streptococcus pyogenes; Pharyngitis and Tonsillitis, caused by Streptococcus pyogenes; Urinary tract infections, including pyelonephritis and cystitis, caused by Escherichia coli, Proteus mirabilis, Klebsiella spp., and coagulase-negative staphylococci; Skin and skin structure infections caused by Staphylococcus aureus and Streptococcus pyogenes. Adverse effects considered to be related to therapy with cefaclor are: Hypersensitivity reactions, Rarely, reversible hyperactivity, agitation, nervousness, insomnia, confusion, hypertonia, dizziness, hallucinations, somnolence and diarrhea. Patients receiving Cefaclor may show a false-positive reaction for glucose in the urine with tests that use Benedict's and Fehling's solutions and also with Clinitest® tablets. There have been reports of increased anticoagulant effect when Cefaclor and oral anticoagulants were administered concomitantly.

Cefoxitin is a cephamycin antibiotic often grouped with the second-generation cephalosporins. It is active against a broad range of gram-negative bacteria including anaerobes. The methoxy group in the 7a position provides cefoxitin with a high degree of stability in the presence of beta-lactamases, both penicillinases and cephalosporinases, of gram-negative bacteria. The bactericidal action of cefoxitin results from inhibition of cell wall synthesis.

Cefadroxil is a new semisynthetic cephalosporin with a broad antibacterial spectrum and a high chemotherapeutic potential when administered orally. Many studies have established the efficacy of the administration of once- or twice-daily cefadroxil in the management of infections in the respiratory tract, urinary tract, skin and soft tissues, and bones and joints.

Cefazolin is a semisynthetic cephalosporin analog with broad-spectrum antibiotic action due to inhibition of bacterial cell wall synthesis. By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, cefazolin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins. Cefazolin is used to treat bacterial infections of the skin, moderately severe bacterial infections involving the lung, bone, joint, stomach, blood, and urinary tract. It is clinically effective against infections caused by staphylococci and streptococci species of Gram positive bacteria. This drug also can be used for perioperative prophylaxis.

Cephalexin is a semisynthetic cephalosporin antibiotic intended for oral administration. In vitro tests demonstrate that the cephalosporins are bactericidal because of their inhibition of cell-wall synthesis. Cephalexin has been shown to be active against most strains of the following microorganisms both in vitro: Staphylococcus aureus (including penicillinase-producing strains), Streptococcus pneumoniae (penicillin-susceptible strains), Streptococcus pyogenes, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Moraxella (Branhamella) catarrhalis, Proteus mirabilis. Cephalexin is indicated for the treatment of the respiratory tract, skin and skin structure, bone and genitourinary tract infections when caused by susceptible strains of the designated microorganisms.

Cefditoren pivoxil is a semi-synthetic cephalosporin antibiotic for oral administration. It is a 3rd generation cephalosporin that is FDA approved for the treatment of acute bacterial exacerbation of chronic bronchitis, community acquired pneumonia, infection of skin and/or subcutaneous tissue, and pharyngitis/tonsillitis. Cefditoren is a cephalosporin with antibacterial activity against gram-positive and gram-negative pathogens. The bactericidal activity of cefditoren results from the inhibition of cell wall synthesis via affinity for penicillin-binding proteins (PBPs). Common adverse reactions include diarrhea, nausea and candida vaginitis. Co-administration of a single dose of an antacid which contained both magnesium (800 mg) and aluminum (900 mg) hydroxides or co-administration of a single dose of intravenously administered famotidine (20 mg) reduced the oral absorption of a single 400 mg dose of cefditoren pivoxil administered following a meal. Co-administration of probenecid with cefditoren pivoxil resulted in an increase in the plasma exposure of cefditoren.

Ceftibuten is a 3rd generation cephalosporin that is FDA approved for the treatment of acute bacterial exacerbations of chronic bronchitis, acute bacterial otitis media, pharyngitis and tonsillitis. Ceftibuten exerts its bactericidal action by binding to essential target proteins of the bacterial cell wall. This binding leads to inhibition of cell-wall synthesis. Common adverse reactions include diarrhea, nausea, vomiting and headache. The effect of increased gastric pH on the bioavailability of ceftibuten was evaluated in 18 healthy adult volunteers. Each volunteer was administered one 400-mg ceftibuten capsule. A single dose of liquid antacid did not affect the Cmax or AUC of ceftibuten; however, 150 mg of ranitidine q12h for 3 days increased the ceftibuten Cmax by 23% and ceftibuten AUC by 16%.

Loracarbef (KT3777) is carbacephem antibiotic structurally identical to cefaclor, except that the sulfur atom of position 1 of the cephem nucleus has been replaced by carbon. It showed good affinity for penicillin-binding proteins. At low concentrations (< 2 mg/L) in vitro, it inhibits Streptococcus pneumoniae, S. pyogenes, beta-haemolytic streptococci groups B, C and G. Proteus mirabilis and Moraxella catarrhalis, including beta-lactamase-producing strains. At therapeutic plasma concentrations it is also active in vitro against most strains of Staphylococcus aureus, S. saprophyticus, Escherichia coli and beta-lactamase-positive and -negative strains of Haemophilus influenzae. Loracarbef has been indicated in the treatment of patients with mild to moderate infections caused by susceptible strains of the designated microorganisms.

Ceftizoxime is a semisynthetic cephalosporin antibiotic, which can be administered intravenously or intramuscularly. It was sold under brand name, cefizox, but was removed from the US Market in 2007. Cefizox was used to treat different infections, such as lower respiratory tract infections caused by Klebsiella spp.; Proteus mirabilis; Escherichia coli; Haemophilus influenza; urinary tract Infections caused by Staphylococcus aureus (penicillinase¬ and nonpenicillinase¬producing); Escherichia coli; Pseudomonas spp. Also for treatment of gonorrhea including uncomplicated cervical and urethral gonorrhea caused by Neisseria gonorrhoeae; pelvic inflammatory disease caused by Neisseria gonorrhoeae, Escherichia coli or Streptococcus agalactiae; meningitis caused by Haemophilus influenza. In addition, some others infections. Cefizox has also been used successfully in the treatment of a limited number of pediatric and adult cases of meningitis caused by Streptococcus pneumoniae. Infections caused by aerobic gram ¬negative and by mixtures of organisms resistant to other cephalosporins, aminoglycosides, or penicillins have responded to treatment with Cefizox. The bactericidal action of ceftizoxime results from inhibition of the third and last stage of bacterial cell wall synthesis. Bacterial cell wall autolytic enzymes such as autolysins then mediate cell lysis; it is possible that ceftizoxime interferes with an autolysin inhibitor. Ceftizoxime is highly resistant to a broad spectrum of beta -lactamases (penicillinase and cephalosporinase), including Richmond types II, III, TEM, IV, produced by both aerobic and anaerobic gram - positive and gram - negative organisms and I.

Cefoperazone (marketed under the name Cefobid) is a third-generation cephalosporin antibiotic. Cefoperazone has a broad spectrum of activity: Respiratory Tract Infections caused by S. pneumoniae, H. influenzae, S. aureus (penicillinase and non-penicillinase producing strains), S. pyogenes (Group A beta-hemolytic streptococci), P. aeruginosa, Klebsiella pneumoniae, E. coli, Proteus mirabilis, and Enterobacter species. Peritonitis and Other Intra-abdominal Infections caused by E. coli, P. aeruginosa, and anaerobic gram-negative bacilli (including Bacteroides fragilis). Bacterial Septicemia caused by S. pneumoniae, S. agalactiae, S. aureus, Pseudomonas aeruginosa, E. coli, Klebsiella spp., Klebsiella pneumoniae, Proteus species (indole-positive and indole-negative), Clostridium spp. and anaerobic gram-positive cocci. Infections of the Skin and Skin Structures caused by S. aureus (penicillinase and non-penicillinase producing strains), S. pyogenes, and P. aeruginosa. Pelvic Inflammatory Disease, Endometritis, and Other Infections of the Female Genital Tract caused by N. gonorrhoeae, S. epidermidis, S. agalactiae, E. coli, Clostridium spp., Bacteroides species (including Bacteroides fragilis), and anaerobic gram-positive cocci. Cefobid has no activity against Chlamydia trachomatis. Therefore, when Cefobid is used in the treatment of patients with pelvic inflammatory disease and C. trachomatis is one of the suspected pathogens, appropriate anti-chlamydial coverage should be added. Urinary Tract Infections caused by Escherichia coli and Pseudomonas aeruginosa. Cefoperazone, a third-generation cephalosporin, interferes with cell wall synthesis by binding to the penicillin-binding proteins (PBPs), thus preventing cross-linking of nascent peptidoglycan. Cefoperazone is stable to penicillinases and has a high degree of stability to many beta-lactamases produced by gram-negative bacteria. When tested in vitro, cefoperazone has demonstrated synergistic interactions with aminoglycosides against gram-negative bacilli. As with all cephalosporins, hypersensitivity manifested by skin reactions or drug fever. Reversible neutropenia may occur with prolonged administration. Diarrhea or loose stools has been reported also.