Ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid) is the synthetic antimicrobial agent for oral or intravenous administration. Ciprofloxacin is a member of the fluoroquinolone class of antibacterial agents. The bactericidal action of ciprofloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV (both Type II topoisomerases), which are required for bacterial DNA replication, transcription, repair, and recombination. Ciprofloxacin is used to treat a wide variety of infections, including infections of bones and joints, endocarditis, gastroenteritis, malignant otitis externa, respiratory tract infections, cellulitis, urinary tract infections, prostatitis, anthrax, and chancroid. In the United States, ciprofloxacin is pregnancy category C. This category includes drugs for which no adequate and well-controlled studies in human pregnancy exist, and for which animal studies have suggested the potential for harm to the fetus, but potential benefits may warrant use of the drug in pregnant women despite potential risks. Fluoroquinolones have been reported as present in a mother's milk and thus passed on to the nursing child. Oral and intravenous ciprofloxacin is approved by the FDA for use in children for only two indications due to the risk of permanent injury to the musculoskeletal system: Inhalational anthrax (postexposure) and Complicated urinary tract infections and pyelonephritis due to Escherichia coli.

Aztreonam is the first monocyclic beta-lactam antibiotic (monobactam) originally isolated from Chromobacterium violaceum. Aztreonam has a high affinity for the protein-binding protein 3 (PBP-3) of aerobic gram-negative bacteria. Most of these organisms are inhibited and killed at low concentrations of the drug. Aztreonam must be administered as an intravenous or intramuscular injection (AZACTAM®), or inhaled (CAYSTON®). Aztreonam for injection is indicated for the treatment of the following infections caused by susceptible gram-negative microorganisms: urinary tract, lower respiratory tract, skin and skin-structure, intra-abdominal and gynecologic infections as well as for septicemia. Aztreonam for inhalation solution is indicated to improve respiratory symptoms in cystic fibrosis patients with Pseudomonas aeruginosa.

Ceftazidime is a semisynthetic, broad-spectrum, beta-lactam antibiotic, used especially for Pseudomonas and other gram-negative infections in debilitated patients. Ceftazidime is used to treat lower respiratory tract, skin, urinary tract, blood-stream, joint, and abdominal infections, and meningitis. The drug is given intravenously (IV) or intramuscularly (IM) every 8–12 hours (two or three times a day), with dose and frequency varying by the type of infection, severity, and/or renal function of the patient. Injectable formulations of ceftazidime are currently nebulized "off-label" to manage Cystic Fibrosis, non-Cystic Fibrosis bronchiectasis, drug-resistant nontuberculous mycobacterial infections, ventilator-associated pneumonia, and post-transplant airway infections. Ceftazidime is generally well-tolerated. When side effects do occur, they are most commonly local effects from the intravenous line site, allergic reactions, and gastrointestinal symptoms. According to one manufacturer, in clinical trials, allergic reactions including itching, rash, and fever, happened in fewer than 2% of patients. Rare but more serious allergic reactions, such as toxic epidermal necrolysis, Stevens-Johnson syndrome, and erythema multiforme, have been reported with this class of antibiotics, including ceftazidime. Gastrointestinal symptoms, including diarrhea, nausea, vomiting, and abdominal pain, were reported in fewer than 2% of patients.

Imipenem is a beta-lactam antibiotic belongings to the subgroup of carbapenems. Imipenem has a broad spectrum of activity against aerobic and anaerobic Gram positive as well as Gram negative bacteria. It is particularly important for its activity against Pseudomonas aeruginosa and the Enterococcus species. Imipenem is rapidly degraded by the renal enzyme dehydropeptidase when administered alone, and is always co-administered with cilastatin to prevent this inactivation. The bactericidal activity of imipenem results from the inhibition of cell wall synthesis. Its greatest affinity is for penicillin binding proteins (PBPs) 1A, 1B, 2, 4, 5 and 6 of Escherichia coli, and 1A, 1B, 2, 4 and 5 of Pseudomonas aeruginosa. The lethal effect is related to binding to PBP 2 and PBP 1B. Imipenem is marketed under the brand name Primaxin. PRIMAXIN I.M. (Imipenem and Cilastatin for Injectable Suspension) is a formulation of imipenem (a thienamycin antibiotic) and cilastatin sodium (the inhibitor of the renal dipeptidase, dehydropeptidase I). PRIMAXIN I.M. is a potent broad spectrum antibacterial agent for intramuscular administration.

Cefotetan is a semisynthetic cephamycin antibiotic that is administered intravenously or intramuscularly. The drug is highly resistant to a broad spectrum of beta-lactamases and is active against a wide range of both aerobic and anaerobic gram-positive and gram-negative microorganisms. It is FDA approved for the treatment of urinary tract infection, lower respiratory tract infection, skin and skin structure infections, gynecologic infection, intra-abdominal infection, and bone and joint infection; and for prophylaxis of postoperative infection. The bactericidal action of cefotetan results from inhibition of cell wall synthesis. The methoxy group in the 7-alpha position provides cefotetan with a high degree of stability in the presence of beta-lactamases including both penicillinases and cephalosporinase of gram-negative bacteria. Common adverse reactions include diarrhea and nausea. As with other cephalosporins, high concentrations of cefotetan may interfere with measurement of serum and urine creatinine levels.

Ceftriaxone is a broad-spectrum cephalosporin antibiotic with a very long half-life. Ceftriaxone is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis. Ceftriaxone has activity in the presence of some beta-lactamases, both penicillinases and cephalosporinases, of Gram-negative and Gram-positive bacteria. It is approved for the treatment of lower respiratory tract infections, acute bacterial otitis media, skin infections, urinary tract infections, pelvic inflammatory disease, bacterial septicemia, bone and joint infections, intraabdominal infection, meningitis, and surgical prophylaxis. Common adverse reactions include erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, pseudomembranous enterocolitis, hemolytic anemia, hypersensitivity reaction, kernicterus, renal failure, and lung injury. Vancomycin, amsacrine, aminoglycosides, and fluconazole are incompatible with Ceftriaxone in admixtures. Precipitation of Ceftriaxone-calcium can occur when Ceftriaxone for Injection is mixed with calcium-containing solutions in the same intravenous administration line.

Clavulanic acid is produced by the fermentation of Streptomyces clavuligerus. It is a β-lactam structurally related to the penicillins and possesses the ability to inactivate a wide variety of β-lactamases by blocking the active sites of these enzymes. Clavulanic acid is particularly active against the clinically important plasmid-mediated β-lactamases frequently responsible for transferred drug resistance to penicillins and cephalosporins. Clavulanic acid is used in conjunction with amoxicillin for the treatment of bronchitis and urinary tract, skin, and soft tissue infections caused by beta-lactamase producing organisms. Clavulanic acid competitively and irreversibly inhibits a wide variety of beta-lactamases, commonly found in microorganisms resistant to penicillins and cephalosporins. Binding and irreversibly inhibiting the beta-lactamase results in a restauration of the antimicrobial activity of beta-lactam antibiotics against lactamase-secreting-resistant bacteria. By inactivating beta-lactamase (the bacterial resistance protein), the accompanying penicillin/cephalosporin drugs may be made more potent as well.

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.

Clindamycin phosphate is the prodrug of clindamycin with no antimicrobial activity in vitro but can be rapidly converted in vivo to the parent drug, clindamycin, by phosphatase ester hydrolysis. It is indicated in the treatment of serious infections caused by susceptible anaerobic bacteria: Lower respiratory tract infections including pneumonia, empyema, and lung abscess caused by anaerobes; Skin and skin structure infections; Gynecological infections including endometritis, nongonococcal tubo-ovarian abscess, pelvic cellulitis, and postsurgical vaginal cuff infection caused by susceptible anaerobes; Intra-abdominal infections; Septicemia; Bone and joint infections. Orally and parenterally administered clindamycin has been associated with severe colitis, which may end fatally. Abdominal pain, gastrointestinal disturbances, gram-negative folliculitis, eye pain and contact dermatitis have also been reported in association with the use of topical formulations of clindamycin. Clindamycin has been shown to have neuromuscular blocking properties that may enhance the action of other neuromuscular blocking agents