Cephalosporins emerged as the most important class of antimicrobial agents for prophylaxis. These drugs have a broad spectrum and relatively low incidence of adverse reactions. Cefazolin (1 g) appears to be widely used in the United States by gynecologic surgeons because of its relatively low cost and long half-life (1.8 hours). Other cephalosporins such as cefoxitin, cefotaxime, and cefotetan commonly are used for prophylaxis. These agents appear to have a broader spectrum of activity against anaerobic bacteria and are appropriate selections when colorectal resections are possible, such as during a debulking surgery for ovarian cancer. For the majority of gynecologic procedures, there is little evidence that a clinically relevant distinction exists between cefazolin and the other agents. Morbidly obese patients, defined as having a BMI greater than 35 or weight greater than 100kg, should receive2gof cefazolin to achieve appropriate blood and tissue antibiotic concentrations (71).
Antimicrobial prophylaxis, although usually beneficial, is not without risk. Anaphylaxis is the most life-threatening complication from antibiotic use. Anaphylactic reactions to penicillins are reported in 0.2% courses of treatment. The fatality rate is 0.0001%. Data indicate that it is safe to administer cephalosporins to women who report a history of adverse reactions to penicillins. The incidence of adverse reactions (e.g., skin ﬂushing, itching) in women with a history of penicillin allergy who are given cephalosporins is 1% to 10%. The incidence of anaphylaxis in this setting is less than 0.02% (72).
A single dose of broad-spectrum antibiotics can result in pseudomembranous colitis, caused by Clostridium difficile. Diarrhea may develop in as many as 15% of hospitalized patients treated with beta-lactam antibiotics (73). In patients receiving clindamycin, the rate of diarrhea is nearly 10% to 25% (74). These gastrointestinal complications from antibiotics may cause serious morbidity in the surgical patient, and the surgeon should be able to recognize and manage these problems.
Not all gynecologic surgery patients need to receive prophylactic antibiotics. The surgeon should choose agents to cover procedures based on available data, thereby avoiding the potential for adverse reactions and minimizing the unnecessary use of antibiotics, which may contribute to increased rates of antimicrobial resistance. In patients with cephalosporin allergies or anaphylaxis to penicillin, other drugs or combinations should be chosen to provide adequate prophylactic coverage. Antimicrobial prophylaxis options for common gynecologic procedures are presented in Table 22.6. Antibiotic prophylaxis is not indicated for diagnostic or operative laparoscopy, exploratory laparotomy, or diagnostic or operative hysteroscopy, including endometrial ablation, intrauterine device insertions, endometrial biopsy, or urodynamics (75).
It was thought that women who had severe valvular disease or other cardiac conditions required antibiotic prophylaxis prior to genitourinary (GU) or gastrointestinal (GI) procedures in order to prevent bacterial endocarditis as a result of the transient bacteremia provoked by the surgery. After reviewing the pertinent evidence-based literature, the American Heart Association issued revised guidelines in 2007 stating that antibiotic prophylaxis was not necessary solely to prevent endocarditis in patients undergoing GI or GU procedures, including hysterectomy (Table 22.8) (76).
Table 22.8 Recommendations for Prophylaxis of Bacterial Endocarditis