Surgical Prophylaxis

Important considerations are:

• Activity against potential pathogens.
• Prevention of resistance - broad spectrum antimicrobials have greater potential to increase resistance than narrow spectrum antimicrobials.
• Appropriate timing - give the pre-operative dose within 60 minutes of surgical incision to ensure adequate concentrations during the time of potential contamination. Vancomycin requires a longer infusion time (2-3 hours) so aim to start the infusion 1-2 hours pre-operatively.
• Duration - usually one parenteral dose is sufficient for routine prophylaxis. A second dose may be necessary for longer surgeries or where there is excessive intra-operative blood loss. As a general rule, re-dose if the procedure exceeds two half-lives of the antimicrobial (see Table). The exception is gentamicin, which should not be re-dosed (see Table).

  Antimicrobial	Half-life (approximate) in adults with normal renal function	Recommended re‑dosing interval (from initiation of pre‑operative dose)
  amoxicillin/ clavulanic acid	2 h (amoxicillin)	4 h
  cefazolin	2 h	4 h
  cefuroxime	2 h	4 h
  clindamycin	3 h	6 h
  gentamicin	3 h	Do not re‑dose
  metronidazole	8 h	Usually no need to re‑dose
  piperacillin/tazobactam	1 h	2 h
  vancomycin	6 h	Usually no need to re‑dose

Prophylactic antimicrobials should be prescribed ‘stat’ on the drug chart.

• Cost - total cost of drug use including administration.

Topic Code: 99271

must be prescribed or recommended by a consultant.