Cefazolin as the mainstay for antibiotic prophylaxis in patients with a penicillin allergy in obstetrics and gynecology.

Cefazolin is the most common antibiotic used for prophylaxis in obstetrics and gynecology. Among those with a penicillin allergy, alternative antibiotics are often chosen for prophylaxis, given fears of cross-reactivity between penicillin and cefazolin. Alternative antibiotics in this setting are associated with adverse sequelae, including surgical site infection, induction of bacterial resistance, higher costs to the healthcare system, and possible Clostridium difficile infection. Given the difference in R1 side chains between penicillin and cefazolin, cefazolin use is safe and should be recommended for patients with a penicillin allergy, including those who experience Immunoglobulin E-mediated reactions such as anaphylaxis. Cefazolin should only be avoided in those who experience a history of a severe, life-threatening delayed hypersensitivity reaction manifested as severe cutaneous adverse reactions (Steven-Johnson Syndrome), hepatitis, nephritis, serum sickness, and hemolytic anemia in response to penicillin administration. In addition, >90% of those with a documented penicillin allergy do not have true allergies on skin testing. Increased referral for penicillin allergy testing should be incorporated into routine obstetric care and preoperative assessment to reduce suboptimal antibiotic prophylaxis use. More education is needed among providers surrounding penicillin allergy assessment and cross-reactivity among penicillins and cephalosporins to optimize antibiotic prophylaxis in obstetrics and gynecology.