Author: Brian Holtry

Ertapenem is a synthetic carbapenem b-lactam antibiotic that is structurally and pharmacologically related to imipenem and meropenem. Like meropenem but unlike imipenem, ertapenem has a methyl group at position 1 of the 5-membered ring, which confers stability against hydrolysis by dehydropeptidase 1 (DHP 1) present on the brush border of proximal renal tubular cells, and therefore does not require concomitant administration with a DHP-1 inhibitor such as cilastatin. Ertapenem is almost completely absorbed following IM administration, having a mean bioavailability of 90%.

Ceftriaxone is used for the treatment of bone and joint infections, endocarditis, intra-abdominal infections, meningitis and other CNS infections, otitis media, respiratory tract infections,septicemia, skin and skin structure infections, and urinary tract infections caused by susceptible bacteria.

Ceftizoxime is used for the treatment of bone and joint infections, intra-abdominal infections, meningitis, lower respiratory tract infections, septicemia, skin and skin structure infections, and urinary tract infections caused by susceptible bacteria. The drug also is used for the treatment of gonorrhea and pelvic inflammatory disease.

Ceftibuten is used orally for the treatment of mild to moderate respiratory tract infections (i.e., acute exacerbations of chronic bronchitis) caused by susceptible bacteria. The drug also is used orally for the treatment of acute otitis media caused by susceptible bacteria and pharyngitis and tonsillitis caused by Streptococcus pyogenes (group A b-hemolytic streptococci). Oral ceftibuten is used for the treatment of acute exacerbations of chronic bronchitis caused by susceptible Streptococcus pneumoniae (penicillin-susceptible strains only), Haemophilus influenzae (including b-lactamase-producing strains), or Moraxella (formerly Branhamella) catarrhalis (including b-lactamase-producing strains.

Like other parenteral third generation cephalosporins (cefoperazone, cefotaxime, ceftizoxime, ceftriaxone), ceftazidime is less active than first and second generation cephalosporins against some gram-positive bacteria (e.g., staphylococci) and generally should not be used in the treatment of infections caused by these organisms when a penicillin or first or second generation cephalosporin could be used.

Prior to initiation of cefotaxime therapy, appropriate specimens should be obtained for identification of the causative organism and in vitro susceptibility tests. If cefotaxime therapy is started pending results of susceptibility tests, it should be discontinued if the causative organism is found to be resistant to the drug. Cefotaxime generally should not be used in the treatment of infections caused by gram-positive bacteria when a penicillin or a first generation cephalosporin could be used. Although cefotaxime has been effective in the treatment of cellulitis, wound infections, septicemia, and lower respiratory tract infections caused by susceptible staphylococci or streptococci, treatment failures have been reported when the drug was used in the treatment of osteomyelitis caused by S. aureus.

Prior to initiation of cefoperazone therapy, appropriate specimens should be obtained for identification of the causative organism and in vitro susceptibility tests. Cefoperazone may be started pending results of susceptibility tests but should be discontinued if the causative organism is found to be resistant to the drug. In serious infections when the causative organism is unknown, concomitant therapy with an aminoglycoside may be indicated pending results of in vitro susceptibility tests. However, in vitro studies indicate that cefoperazone is less active on a weight basis than cefotaxime, ceftizoxime, and ceftriaxone against susceptible Enterobacteriaceae, and other cephalosporins (e.g., cefepime, cefotaxime, ceftazidime, ceftriaxone, ceftizoxime) generally are preferred when a parenteral cephalosporin is indicated for the treatment of infections known or suspected to be caused by Enterobacteriaceae.

The drug also is used for the treatment of uncomplicated gonorrhea and has been used in the treatment of infections caused by susceptible Salmonella or Shigella. Because cefixime has a long serum half-life and can be administered once or twice daily, some clinicians suggest that the drug may be particularly useful when patient compliance is a concern (e.g., in the treatment of otitis media). Although cefixime is an effective alternative to other anti-infective agents for the treatment of many infections, the drug offers no clear advantage (except for a convenient dosage regimen) over other equally effective, less expensive anti-infectives available for the treatment of uncomplicated urinary tract infections or upper and lower respiratory tract infections.