Surgical antibiotic prophylaxis for patients receiving treatment for established infection

If the patient is being treated with antibiotic therapy for established infection, it is not necessary to give additional antibiotic prophylaxis, provided the treatment regimen has activity against the organism(s) most likely to cause postoperative infection. However, adjust the timing of the treatment dose to achieve adequate plasma and tissue concentrations at the time of surgical incision and for the duration of the procedure. In general, if more than two half-lives of the drug have elapsed since the previous dose, an additional dose should be given—seek expert advice.