Antibacterial drugs

Chloramphenicol should be used only for the treatment of serious infections caused by susceptible bacteria or Rickettsia when potentially less toxic drugs are ineffective or contraindicated. The drug must not be used for the treatment of trivial infections, as a prophylactic agent to prevent bacterial infections, or when it is not indicated as in the treatment of colds, influenza, or throat infections.

The drug should not be used alone for empiric therapy in seriously ill patients if there is a possibility that the infection may be caused by gram-positive bacteria or if a mixed aerobic-anaerobic bacterial infection is suspected. In such infections, another anti-infective agent effective against the suspected, potentially aztreonam-resistant organism should initially be used concomitantly. Aztreonam has been used safely and effectively in conjunction with an aminoglycoside, clindamycin, erythromycin, metronidazole, a penicillin, or vancomycin.

Cefoxitin is used in the treatment of serious infections of the lower respiratory tract, skin and skin structure, bone and joint, and urinary tract; septicemia; gynecologic infections (including endometritis, pelvic cellulitis, and pelvic inflammatory disease); and intra-abdominal infections (including peritonitis and intra-abdominal abscess) caused by susceptible bacteria. Cefoxitin also has been used in the treatment of uncomplicated gonorrhea and is used for perioperative prophylaxis. Prior to and during cefoxitin therapy, the causative organism should be cultured and in vitro susceptibility tests conducted. In serious infections, therapy may be initiated pending results of in vitro tests.

Cefotetan should not be used in the treatment of meningitis or other CNS infections. Prior to initiation of cefotetan therapy, appropriate specimens should be obtained for identification of the causative organism and in vitro susceptibility tests. Cefotetan therapy may be started pending results of susceptibility tests, but should be discontinued if the organism is found to be resistant to the drug.

Imipenem and cilastatin sodium is a fixed combination of imipenem monohydrate (a semisynthetic carbapenem b-lactam antibiotic) and cilastatin sodium, 1, 35 which prevents renal metabolism of imipenem by dehydropeptidase I (DHP I).

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.