Medication Summary
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.
Antibiotics
Class Summary
A combination therapy with clindamycin and an aminoglycoside is considered the criterion standard by which most antibiotic clinical trials are judged. A combination regimen of ampicillin, gentamicin, and metronidazole provides coverage against most of the organisms that are encountered in serious pelvic infections. Doxycycline should be used if Chlamydia is the cause of the endometritis.
Ampicillin sulbactam can be used as monotherapy. Single-agent therapies have been found to be effective in 80-90% of patients.
Clindamycin (Cleocin)
Clindamycin, which is used in combination with gentamicin, is a lincosamide that is useful as a treatment against serious skin and soft tissue infections caused by most staphylococci strains. It is also effective against aerobic and anaerobic streptococci, except enterococci.
Clindamycin inhibits bacterial protein synthesis by inhibiting peptide chain initiation at the bacterial ribosome. It preferentially binds to the 50S ribosomal subunit, causing bacterial growth inhibition.
Gentamicin (Gentacidin, Garamycin)
An aminoglycoside antibiotic used for gram-negative bacterial coverage, gentamicin is used in combination with either clindamycin or in combination with metronidazole and ampicillin. Dosing regimens are numerous and are adjusted based on creatinine clearance and changes in the volume of distribution. Doses may be given IV or IM.
Ampicillin (Omnipen, Marcillin)
Ampicillin is used in combination with gentamicin and metronidazole. It interferes with bacterial cell-wall synthesis during active multiplication, causing bactericidal activity against susceptible organisms.
Metronidazole (Flagyl, Flagyl ER)
Used in combination with gentamicin and ampicillin, metronidazole is an imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa. Metronidazole appears to be absorbed into the cells and the intermediate-metabolized compounds that are formed bind DNA and inhibit protein synthesis, causing cell death.
Ampicillin and sulbactam (Unasyn)
The combination of ampicillin with the beta-lactamase inhibitor sulbactam sodium has been found to be effective as monotherapy in 80-90% of patients. This agent covers skin, enteric flora, and anaerobes. It is not ideal for nosocomial pathogens.
Doxycycline (Bio-Tab, Doryx, Vibramycin)
Doxycycline is used if Chlamydia is the cause of the endometritis. It inhibits protein synthesis and thus bacterial growth by binding with the 30S and possibly the 50S ribosomal subunits of susceptible bacteria.
Ertapenem (Invanz)
The bactericidal activity of ertapenem results from inhibition of cell wall synthesis and is mediated through ertapenem binding to penicillin binding proteins. This agent is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, cephalosporinases, and extended-spectrum beta-lactamases. It is hydrolyzed by metallo-beta-lactamases.
Cefoxitin (Mefoxin)
Cefoxitin is a second-generation cephalosporin indicated for gram-positive cocci and gram-negative rod infections. Infections caused by cephalosporin- or penicillin-resistant gram-negative bacteria may respond to cefoxitin.
Piperacillin and tazobactam sodium (Zosyn)
The combination of ampicillin with the beta-lactamase inhibitor sulbactam sodium has been found to be effective as monotherapy in 80-90% of patients. This agent covers skin, enteric flora, and anaerobes. It is not ideal for nosocomial pathogens.
Cefotetan
Cefotetan is second generation and is used as a single-drug therapy to provide broad gram-negative coverage, broad anaerobic coverage, and some coverage against gram-positive bacteria. It inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins, and it inhibits the final transpeptidation step of peptidoglycan synthesis, resulting in cell wall death.
Cefotaxime (Claforan)
Cefotaxime is a third generation cephalosporin with a broad gram-negative spectrum, lower efficacy against gram-positive organisms, and higher efficacy against resistant organisms. It arrests bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins, which, in turn, inhibits bacterial growth. It is used for septicemia and the treatment of gynecologic infections caused by susceptible organisms.
Ceftazidime (Fortaz, Tazicef)
Ceftazidime is a third generation cephalosporin with broad-spectrum, gram-negative activity, including pseudomonal organisms. It has lower efficacy against gram-positive organisms and higher efficacy against resistant organisms. It arrests bacterial growth by binding to one or more penicillin-binding proteins, which, in turn, inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell wall synthesis, thus inhibiting cell wall biosynthesis.
Cefazolin
Cefazolin is a first-generation cephalosporin, which by binding to 1 or more penicillin-binding proteins, arrests bacterial cell wall synthesis and inhibits bacterial replication. Prophylactic antibiotics reduce the incidence of postpartum febrile morbidity in patients undergoing cesarean delivery. Current research supports the use of preoperative administration of prophylactic antibiotics. Single-agent therapy with a first-generation such as cefazolin or a second-generation cephalosporin has been considered the best choice.
Levofloxacin (Levaquin)
Levofloxacin is a fluoroquinolone antibiotic. It is used for pseudomonal infections and infections due to multidrug resistant gram-negative organisms. A trend toward the use of broad-spectrum monotherapy has emerged, and these agents are generally effective in 80-90% of patients. Cephalosporins, extended-spectrum penicillins, and fluoroquinolones are used as monotherapy. If gonococcal infection is suspected, levaquin is contraindicated because many strains of the organism are now resistant to the quinolones.
